Page summary

https://en.wikipedia.org/wiki/Sweden

Tested 2026-09-20 14:28:58 using Chrome 152.0.7977.64 (runtime settings)

SummaryWaterfallMetricsRenderingCoachPageXrayCPU

This page is fast to paint and visually stable, but janky to interact with, loose on best practices and weak on user privacy.

82 / 100
Coach overall
84 / 100
Performance
80 / 100
Best practice
80 / 100
Privacy

How it loaded →

0 → 4.900 s · median run
Frame at 0 ms
start
Frame at 1600 ms
Largest paint1.600 s
Frame at 2200 ms
2.200 s
Frame at 3100 ms
3.100 s
Frame at 4400 ms
4.400 s
Frame at 4900 ms
Complete4.900 s
1.300 s
First Visual Change
2.577 s
Speed Index
4.833 s
Visual Complete 85%
4.900 s
Last Visual Change
TTFB404 msLCP1.288 sTBT1.429 sCLS0.00

What to act on · top recommendations

Avoid CPU Long Tasks

0 / 100

The page has 16 CPU long tasks with the total of 2.596 s. The total blocking time is 1.429 s and 3 long tasks before first contentful paint with total time of 517 ms. However the CPU Long Task is depending on the computer/phones actual CPU speed, so you should measure this on the same type of the device that your user is using. Use Geckoprofiler for Firefox or Chromes tracelog to debug your long tasks.

Serve images in modern formats (AVIF, WebP)

0 / 100

The page ships 74 images (out of 74) in JPEG/PNG/GIF without a modern alternative. Wrap them in a <picture> with a <source type="image/avif"> or "image/webp" before the legacy <img>, or serve modern formats from your image pipeline directly. AVIF and WebP usually deliver 25–50% smaller files at the same quality.

Avoid extra requests by setting cache headers

0 / 100

The page has 13 requests that are missing a cache time. Configure a cache time so the browser doesn't need to download them every time. It will save 387.8 kB the next access.

Google Web Vitals

min · median · mean · max of 3 runs
MetricMinMedianMeanMaxRuns agree?
Time To First Byte (TTFB)404 ms404 ms405 ms406 msstable ±1%
Largest Contentful Paint (LCP)1.276 s1.288 s1.360 s1.516 svaries ±9%
Cumulative Layout Shift (CLS)0000identical

Visual Metrics

min · median · mean · max of 3 runs
MetricMinMedianMeanMaxRuns agree?
First visual change1.267 s1.300 s1.367 s1.533 sruns disagree ±10%
Last visual change4.833 s4.900 s4.922 s5.033 sstable ±2%
Speed index2.498 s2.577 s2.576 s2.654 sstable ±3%
Largest image1.267 s1.300 s1.367 s1.533 sruns disagree ±10%
Heading4.467 s4.500 s4.545 s4.667 sstable ±2%
Largest contentful paint4.467 s4.500 s4.545 s4.667 sstable ±2%
Last meaningful paint4.467 s4.500 s4.545 s4.667 sstable ±2%
Visual readiness3.500 s3.566 s3.555 s3.600 sstable ±1%
Visual complete 854.600 s4.833 s4.778 s4.900 sstable ±3%
Visual complete 954.800 s4.833 s4.844 s4.900 sstable ±1%
Visual complete 994.833 s4.900 s4.922 s5.033 sstable ±2%

CPU

min · median · mean · max of 3 runs
MetricMinMedianMeanMaxRuns agree?
Total Blocking Time1.273 s1.429 s1.397 s1.490 svaries ±8%
Max Potential FID440 ms449 ms472 ms527 msvaries ±10%
CPU long tasks 14141516varies ±7%
CPU last long task happens at4.603 s4.630 s4.646 s4.704 sstable ±1%

More metrics

min · median · mean · max of 3 runs
MetricMinMedianMeanMaxRuns agree?
First paint1.276 s1.288 s1.360 s1.516 svaries ±9%
Load event end2.490 s2.526 s2.531 s2.576 sstable ±2%

User Timing

min · median · mean · max of 3 runs
MetricMinMedianMeanMaxRuns agree?
mwStartup2.033 s2.083 s2.088 s2.147 sstable ±3%
mwCentralNoticeBanner4.382 s4.425 s4.463 s4.582 sstable ±2%

Waterfall

Run 2 SpeedIndex median

First paintFCPLCPDOMContentLoadedDOM interactiveLoadRender-blockingRedirectError

Rendering

Run 2 · median
0.000 s
0s1s2s3s4s5s

The red band on the timeline marks when the main thread was busy with long tasks: moments when the page could not paint or respond, however the video looks.

Download video

Filmstrip

20 frames

Use --filmstrip.showAll to show all filmstrips.

Frame at 0 ms
0 ms
0 %
Frame at 800 ms
800 ms
0 %
Frame at 1.000 s
1.000 s
0 %
Frame at 1.300 s
1.300 s
63 %
Frame at 1.600 s
1.600 s
64 %
Frame at 1.700 s
1.700 s
64 %
Frame at 1.900 s
1.900 s
64 %
Frame at 2.100 s
2.100 s
64 %
Frame at 2.200 s
2.200 s
64 %
Frame at 2.600 s
2.600 s
64 %
Frame at 2.900 s
2.900 s
64 %
Frame at 3.100 s
3.100 s
64 %
Frame at 3.200 s
3.200 s
64 %
Frame at 3.400 s
3.400 s
64 %
Frame at 4.100 s
4.100 s
64 %
Frame at 4.400 s
4.400 s
64 %
Frame at 4.600 s
4.600 s
64 %
Frame at 4.700 s
4.700 s
73 %
Frame at 4.800 s
4.800 s
73 %
Frame at 4.900 s
4.900 s
100 %

Click a frame to seek the video to that moment. The dot marks frames where the page changed visually.

Visual instability

54.22 % of pixels ever changed · 0.01 % changed 5+ times
Heatmap of how often each pixel changed while the page loaded

The whole recording in one image: every pixel is tinted by how often it changed. Amber changed once, deep red changed ten or more times. The scale is fixed, so heatmaps from different runs compare directly.

Flat amber is a page that painted once and stayed put. Red speckle in the shape of the text means the same pixels repainted over and over, usually invisible rendering noise that inflates Last Visual Change and Speed Index. A solid red block is a genuinely restless area, like an ad or a carousel.

Frames

How smoothly Chrome delivered frames to the screen during the test. Dropped counts only frames Chrome flags as affecting smoothness. On mostly-static pages the longest gap includes idle time where there was simply nothing to draw.

Frames shown60
Partial15
Dropped15
Effective FPS14.8
Longest gap946 msat 2.213 s

Why was rendering delayed?

Rendering was not meaningfully delayed. First paint landed at 1.288 s on a 404 ms first byte; the 2 render-blocking requests were done by 854 ms and the remaining ~434 ms is style and layout work (196 ms of it measured style recalculation).

Style recalculation

measured by Chrome during this run

Style the browser had to recalculate before it could paint: many elements or a lot of time spent here points at expensive CSS on the critical rendering path. The recalculation count and the largest single one tell the two problems apart: one massive style change touching most of the page (few recalculations, the largest close to the total) needs different medicine than thousands of tiny ones (many recalculations, each tiny).

One large recalculation dominates. Restyling 803 elements cost 196 ms before the page painted (15.2 % of the time to First Contentful Paint), and a single recalculation of 791 elements accounts for 191 ms of it. Look for one class or inline-style change on a large container near the top of the DOM that restyles the whole subtree at once. The changes driving it are listed under Style invalidations below.

Before first & largest contentful paint (same paint, 1.288 s)

Recalculations4
Elements803
Total time196.097 ms
Largest recalculation791 elements · 190.914 ms

The recalculation work before first paint is 15.2 % of the time to First Contentful Paint.

Render blocking requests

3 requests · 49.3 KB

Blocking requests delay both paints: the browser renders nothing until they arrive, so they push First Contentful Paint and everything after it, including the largest paint (LCP). Requests that block the parser inside the body stall everything after them in the document. Load JavaScript with defer or async, and keep non-critical CSS off the critical path with media attributes. Bars show when each request loaded on a clock that runs to the last paint; the gap after the bars is style and layout work.

RequestWhen it loadedTransferDownload
document
en.wikipedia.org · TTFB 404 ms
826 ms
249.0 KB826 ms
ext.cite.parsoid.styles + 17 more modulesblocking
css · load.php styles batch · en.wikipedia.org
394 ms
23.9 KB394 ms
site.stylesblocking
css · load.php styles batch · en.wikipedia.org
378 ms
3.2 KB378 ms
startuppotentially blocking
javascript · load.php startup · en.wikipedia.org
396 ms
22.3 KB396 ms
0322 ms644 msFCP · LCP 1.288 s

Slowest CSS selectorsProfile run

How long Chrome spent testing each CSS selector against the page while recalculating styles. A selector with many match attempts and zero matches is evaluated against the document over and over for rules that never apply.

Not worth optimizing on this page. All selector matching cost 97 ms under the 7× CPU throttle, roughly 14 ms real time, and the worst single selector 25.12 ms. The tables are kept for reference.

Matching time97 ms
Match attempts106 031
Matches7 282
Show the selector tables anyway

Selectors by matching time

top 25
SelectorTimeAttemptsMatches
.client-js.mf-expand-sections-clientpref-0 .mw-parser-output[data-mw-parsoid-version] > section > .mw-heading + div:not(.mf-collapsible-content):has(:target)25.12 ms2690
body.skin--responsive.skin-minerva .mw-parser-output .infobox > tbody > tr2.63 ms8484
:root2.23 ms93
a:where(:not([role="button"]):not(.cdx-menu-item__content)):visited:hover1.81 ms7680
a:where(:not([role="button"]):not(.cdx-menu-item__content)):visited:active1.65 ms7680
a:where(:not([role="button"]):not(.cdx-menu-item__content))1.60 ms384349
.minerva-header .branding-box a1.57 ms3842
.hlist-separated :last-child::after1.57 ms1 83352
a:where(:not([role="button"]):not(.cdx-menu-item__content)):hover1.56 ms3840
.client-js .mw-parser-output[data-mw-parsoid-version] > section > .mw-heading:has(> .mf-collapsible-toggle:focus-visible)1.48 ms600

Wasted selector work: attempts that never match

top 25
SelectorAttemptsTime
blockquote > :only-child1 8330.07 ms
.client-js .outercollapse .innercollapse.mw-collapsible:not(.mw-made-collapsible) :is(tr:not(:first-child), .mw-collapsible-content)1 8330.06 ms
.client-js .outercollapse .innercollapse.mw-collapsible:not(.mw-made-collapsible) > :is(p, table, thead + tbody)1 8330.09 ms
blockquote > :first-child1 8331.43 ms
blockquote > :last-child1 8330.07 ms
.skin-theme-clientpref-night .ns-100 .mw-parser-output :not(.notheme):not(a)1 8330.12 ms
.cdx-message__content > :first-child9940.04 ms
.cdx-message__content > :last-child9940.02 ms
body.mw-mmv-lightbox-open > :not(.mw-notification-area-overlay)9940.07 ms
.cdx-message__content > *9940.05 ms

Style invalidationsProfile run

Why the browser had to recalculate style and layout: every DOM/style change invalidates some set of nodes, and the same class or attribute churning over and over is the pattern to hunt. Counts, not milliseconds: the time is in the style recalculation numbers above.

Chase what keeps changing after the page is up. 510 style recalculations and 480 layout invalidations fired after first paint, on a page the user was already looking at. The biggest driver is attribute title (276×). Start with the script under "Scripts causing invalidations" that keeps triggering it.

Style recalculations517510 after first paint
Layout invalidations1 737480 after first paint

Changes that keep invalidating

top 15
  • attribute: title276×
  • attribute: style86×
  • pseudo: has48×
  • class: mf-collapsible-heading24×
  • pseudo: disabled18×
  • pseudo: enabled18×
  • class: mf-collapsible-content12×
  • attribute: disabled11×
  • attribute: controls
  • class: phase-pre-ready
  • class: state-no-source
  • class: content
  • class: touch-events
  • class: minerva-animations-ready
  • class: page-actions-menu__list-item

Invalidation reasons

split at first paint

After first paint

Invalidations on a page the user was already looking at, the actionable half.

ReasonStyle recalculationsLayout
A :has() selector was re-evaluated:has() re-checks a whole subtree on any change inside it. Scope it tightly, or toggle a class in JavaScript instead.273
A node was inserted into the page112
Related style rule84
JavaScript changed an inline styleSet a class instead of writing element.style, so the browser can batch the work.17
A stylesheet rule changed11
Attribute12
An animation updated stylesAnimate transform and opacity so the compositor can run it off the main thread.1
An element entered layout338
An element left layout88
An element's size changed20
Unknown15
An SVG element changed13
Child changed2
Slider value changed2
A style change forced layout2

Before first paint: building the page

The page being constructed and styled for the first render. Expected work, shown for scale.

ReasonStyle recalculationsLayout
A node was inserted into the page6
A stylesheet rule changed1
An element entered layout1 245
An element left layout2
An element's size changed2
Unknown4
An SVG element changed4

Scripts causing invalidations

top 5

1 animation runs on the main thread instead of on the browser's fast path that animates without blocking other page work (the compositor); they can make the rendering you see above janky. See them on the CPU tab.

Coach

The coach helps you find performance problems on your web page using web performance best practice rules. And gives you advice on privacy and best practices. Tested using Coach-core version 9.2.1.

Performance advice

84
10 warnings2 info
warn(0)Avoid CPU Long TaskslongTasks

The page has 16 CPU long tasks with the total of 2.596 s. The total blocking time is 1.429 s and 3 long tasks before first contentful paint with total time of 517 ms. However the CPU Long Task is depending on the computer/phones actual CPU speed, so you should measure this on the same type of the device that your user is using. Use Geckoprofiler for Firefox or Chromes tracelog to debug your long tasks.

Long CPU tasks locks the thread. To the user this is commonly visible as a "locked up" page where the browser is unable to respond to user input; this is a major source of bad user experience on the web today. However the CPU Long Task is depending on the computer/phones actual CPU speed, so you should measure this on the same type of the device that your user is using. To debug you should use the Chrome timeline log and drag/drop it into devtools or use Firefox Geckoprofiler.

Offenders
  • self
  • self
  • self
  • self
  • self
  • self
  • self
  • self
  • self
  • self
  • self
  • self
  • self
  • self
  • self
  • self
warn(0)Serve images in modern formats (AVIF, WebP)modernImageFormats

The page ships 74 images (out of 74) in JPEG/PNG/GIF without a modern alternative. Wrap them in a <picture> with a <source type="image/avif"> or "image/webp" before the legacy <img>, or serve modern formats from your image pipeline directly. AVIF and WebP usually deliver 25–50% smaller files at the same quality.

AVIF and WebP routinely deliver 25–50% smaller files than JPEG and PNG at the same perceived quality, and every browser version still under support understands at least one of them. Ship modern formats either through a <picture> element with <source type="image/avif"> / "image/webp" entries in front of the legacy <img>, or directly from a content-negotiating image pipeline that returns AVIF / WebP when the client accepts it. https://web.dev/articles/serve-images-webp

Offenders
warn(0)Avoid extra requests by setting cache headerscacheHeaders

The page has 13 requests that are missing a cache time. Configure a cache time so the browser doesn't need to download them every time. It will save 387.8 kB the next access.

The easiest way to make your page fast is to avoid doing requests to the server. Setting a cache header on your server response will tell the browser that it doesn't need to download the asset again during the configured cache time! Always try to set a cache time if the content doesn't change for every request.

Offenders
warn(0)Total JavaScript size shouldn't be too bigjavascriptSize

The total JavaScript transfer size is 291.5 kB and the uncompressed size is 1.1 MB. This is totally crazy! There is really room for improvement here.

A lot of JavaScript often means you are downloading more than you need. How complex is the page and what can the user do on the page? Do you use multiple JavaScript frameworks?

Offenders
URLTransferContent
https://en.wikipedia.org/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=minerva22.3 KB67.2 KB
https://en.wikipedia.org/w/load.php...ia.org/w/load.php10.2 KB22.0 KB
https://en.wikipedia.org/w/load.php...ia.org/w/load.php9.3 KB26.9 KB
https://en.wikipedia.org/w/load.php...ia.org/w/load.php238.7 KB958.8 KB
https://auth.wikimedia.org/metawiki/wiki/Special:CentralAutoLogin/checkLoggedIn...gin/checkLoggedIn1.5 KB254 B
https://meta.wikimedia.org/w/index.php...a.org/w/index.php2.6 KB5.2 KB
warn(60)Don't scale images in the browseravoidScalingImages

The page has 4 images that are scaled more than 100 pixels. It would be better if those images are sent so the browser don't need to scale them.

It's easy to scale images in the browser and make sure they look good in different devices, however that is bad for performance! Scaling images in the browser takes extra CPU time and will hurt performance on mobile. And the user will download extra kilobytes (sometimes megabytes) of data that could be avoided. Don't do that, make sure you create multiple version of the same image server-side and serve the appropriate one.

Offenders
warn(70)Don't use private headers on static contentprivateAssets

The page has 4 requests with private headers. The main page has a private header. It could be right in some cases where the user can be logged in and served specific content. But if your asset is static it should never be private. Make sure that the assets really should be private and only used by one user. Otherwise, make it cacheable for everyone.

If you set private headers on content, that means that the content are specific for that user. Static content should be able to be cached and used by everyone. Avoid setting the cache header to private.

Offenders
infoLong cache headers is goodcacheHeadersLong

The page has 21 requests that have a shorter cache time than one year (but still a cache time).

Setting a cache header is good. Setting a long cache header (a year) is even better because the asset will stay in the browser cache across visits. For content-hashed URLs (e.g. app.4af2.css) you can safely use Cache-Control: max-age=31536000, immutable. For unversioned URLs that may change, use a revalidating strategy instead.

Offenders
infoAdd decoding="async" to non-critical imagesdecodingAsync

The page has 8 images (out of 78) without a decoding hint. Add decoding="async" to non-critical images so the browser can decode them off the main thread.

Setting decoding="async" on an <img> tells the browser it can decode the image off the main thread, which keeps the page responsive to user interactions while images are being processed. The default ("auto") leaves the choice to the browser. https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img#decoding

Offenders
warn(90)Avoid doing redirectsassetsRedirects

The page has 1 redirect. 1 of the redirects are from the base domain, please fix them!

A redirect is one extra step for the user to download the asset. Avoid that if you want to be fast. Redirects are even more of a showstopper on mobile.

Offenders
warn(95)Inline CSS for faster first renderinlineCss

The page has both inline CSS and CSS requests even though it uses a HTTP/2-ish connection. If you have many users on slow connections, it can be better to only inline the CSS. Run your own tests and check the waterfall graph to see what happens.

In the early days of the Internet, inlining CSS was one of the ugliest things you can do. That has changed if you want your page to start rendering fast for your user. Always inline the critical CSS when you use HTTP/1 and HTTP/2 (avoid doing CSS requests that block rendering) and lazy load and cache the rest of the CSS. It is a little more complicated when using HTTP/2. Does your server support HTTP push? Then maybe that can help. Do you have a lot of users on a slow connection and are serving large chunks of HTML? Then it could be better to use the inline technique, becasue some servers always prioritize HTML content over CSS so the user needs to download the HTML first, before the CSS is downloaded.

warn(97)Lazy-load below-the-fold imageslazyLoadingImages

The page has 2 below-the-fold images without loading="lazy". Add loading="lazy" so the browser defers downloading and decoding them until the user scrolls them into view.

Adding loading="lazy" to an <img> tells the browser not to download or decode it until it is close to the viewport. For images that the user may never see (deep in the page, behind a tab, in a footer carousel), this saves bandwidth and main-thread time during initial render. The LCP image and any image in the initial viewport should NOT be lazy-loaded — that delays the first paint. https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img#loading

Offenders
warn(99)Avoid slowing down the critical rendering pathavoidRenderBlocking

The page has 2 blocking requests and 0 in body parser blocking (0 JavaScript and 2 CSS). There are 1 potentially render blocking requests. You need to verify if it is render blocking: https://en.wikipedia.org/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=minerva

The critical rendering path is what the browser needs to do to start rendering the page. Every file requested inside of the head element will postpone the rendering of the page, because the browser need to do the request. Avoid loading JavaScript synchronously inside of the head (you should not need JavaScript to render the page), request files from the same domain as the main document (to avoid DNS lookups) and inline CSS for really fast rendering and a short rendering path.

Offenders

Best practice advice

80
4 info
infoGive every image a textual alternativeimageAltText

The page has 48 images without an alt attribute. Add alt="..." with a description, or alt="" if the image is purely decorative.

Every <img> needs an alt attribute. Use alt="meaningful description" for content images so assistive technologies can announce them, or alt="" (or role="presentation" / aria-hidden="true") for purely decorative images so they are skipped. A missing alt attribute leaves screen reader users with no information at all. https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img#alt

Offenders
infoMeta descriptionmetaDescription

The page is missing a meta description.

Use a page description to make the page more relevant to search engines.

infoAvoid unnecessary headersunnecessaryHeaders

There are 24 responses that sets both a max-age and expires header. There are 39 responses that sets a server header.

Do not send headers that you don't need. We look for p3p, cache-control and max-age, pragma, server and x-frame-options headers. Have a look at Andrew Betts - Headers for Hackers talk as a guide https://www.youtube.com/watch?v=k92ZbrY815c or read https://www.fastly.com/blog/headers-we-dont-want.

Offenders
infoDo not send too long headerslongHeaders

https://en.wikipedia.org/wiki/Sweden has a header content-security-policy that is 4541 characters long. https://en.wikipedia...ia.org/w/load.php has a header sourcemap that is 1462 characters long.

Do not send response headers that are too long.

Offenders

Privacy advice

80
4 warnings2 info
infoSet a Cross-Origin-Embedder-Policy header so cross-origin subresources opt in to being embedded.crossOriginEmbedderPolicyHeader

Set a Cross-Origin-Embedder-Policy header (typically require-corp or credentialless) on the document response to control cross-origin embedding.

Cross-Origin-Embedder-Policy (COEP) makes the page refuse to load cross-origin subresources unless they explicitly opt in via CORP or CORS. Together with Cross-Origin-Opener-Policy it puts the page in a cross-origin isolated context, which mitigates cross-window side-channel attacks (Spectre) and unlocks high-resolution timers and SharedArrayBuffer. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Embedder-Policy

Offenders
warn(0)Set a Cross-Origin-Opener-Policy header to isolate the page from cross-origin windows.crossOriginOpenerPolicyHeader

Set a Cross-Origin-Opener-Policy header (typically same-origin) on the document response to isolate the page from cross-origin windows.

Cross-Origin-Opener-Policy (COOP) lets a page sever its window-group ties to cross-origin documents that opened it or that it opens. Together with Cross-Origin-Embedder-Policy it puts the page in a cross-origin isolated context, which mitigates cross-window side-channel attacks (Spectre) and unlocks high-resolution timers and SharedArrayBuffer. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Opener-Policy

Offenders
infoSet a Cross-Origin-Resource-Policy header to limit who may embed the page.crossOriginResourcePolicyHeader

Set a Cross-Origin-Resource-Policy header (same-origin, same-site or cross-origin) on the document response to limit who may embed it.

Cross-Origin-Resource-Policy (CORP) is a per-response opt-in that tells the browser which origins are allowed to embed the resource. It blocks cross-origin or cross-site no-cors embedding (img, script, iframe, etc.) and is one of the building blocks of cross-origin isolation. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Resource-Policy

Offenders
warn(0)Set a Permissions-Policy header to control which browser features the page can use.permissionsPolicyHeader

Set a Permissions-Policy header to control which browser features the page can use.

The Permissions-Policy response header (the successor to Feature-Policy) lets a site explicitly opt in or out of powerful browser features such as camera, microphone, geolocation, payment and clipboard. Setting a strict policy reduces the attack surface and limits what embedded third parties can do. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Permissions-Policy

Offenders
warn(0)Set a referrer-policy header to make sure you do not leak user information.referrerPolicyHeader

Set a referrer-policy header to make sure you do not leak user information.

Referrer Policy is a new header that allows a site to control how much information the browser includes with navigations away from a document and should be set by all sites. https://scotthelme.co.uk/a-new-security-header-referrer-policy/.

Offenders
warn(30)Use a strict Content-Security-Policy header to mitigate cross-site scripting (XSS) attacks.contentSecurityPolicyHeader

The policy allows 'unsafe-inline', which lets the browser execute inline scripts and styles directly from the page. Move to nonces or hashes plus 'strict-dynamic' so that inline injection cannot run. The policy allows 'unsafe-eval', which lets the page call eval() and Function(). Almost no application needs this; remove it.

A Content-Security-Policy response header tells the browser which sources of script, style, and other content are allowed. The most effective form is a strict CSP using nonces or hashes together with strict-dynamic; the worst is a missing header, with unsafe-inline and unsafe-eval close behind. https://web.dev/articles/strict-csp

Page info

A snapshot of what the browser actually built for this page: the document, how big and deep the DOM tree is and what it kept in storage. Big, deep trees are slower to style and lay out, so the counts Chrome warns about carry a flag.

Page info

Document

What the page says it is and how large it rendered.

TitleSweden - WikipediaThe document title, shown in the browser tab and used by search results.
GeneratorMediaWiki 1.47.0-wmf.20The tool or CMS that generated the HTML, from the page generator meta tag.
Layout viewport361 × 5991 pxThe width the page laid out at, and the full height of the rendered document.

DOM structure

How much markup the browser has to build, style and lay out.

DOM elements10,721Very large, slows layout and styleTotal HTML elements. Fewer means less for the browser to style, lay out and paint.
Avg DOM depth14How deeply elements are nested on average.
Max DOM depth21The deepest nesting on the page. Deep branches cost more style recalculation.
Iframes0No embedded documents on this page.
Script tags6Number of script elements. More scripts usually means more main-thread work.

Storage and connection

What the page stored on the client, and the network it was tested on.

Local storage922.1 KBData the page saved in localStorage, kept across visits.
Session storage0 bData kept in sessionStorage for this tab session only.
Connection type4GWhat the Network Information API reported for the test connection.

Resource hints

3 hints
dns-prefetch
  • https://meta.wikimedia.org/
  • https://en.wikipedia.org/wiki/auth.wikimedia.org
preconnect
  • https://thumb.wikimedia.org/

Technologies used to build the page

Data collected using Coach-core version 9.2.1. With updated code from Webappanalyzer 2026-05-04. Use --browsertime.firefox.includeResponseBodies html or --browsertime.chrome.includeResponseBodies html to help Wappalyzer find more information about technologies used.

Detected technologies

4 technologies

Data from run 2

Visual Metrics

Visual milestones

all times from navigation start
Speed Index2.58 show quickly the page looked done
First Visual Change1.30 sfirst paint reaches the screen
Last Visual Change4.90 sscreen stops changing · 3.60 s after first
nothing painted yet
First Visual Change1.30 s
Visual Complete 85% · Visual Complete 95% · Visual Complete 99% · Last Visual Change4.90 s
Visual Readiness3.60 s· first to last change
01.0 s2.0 s3.0 s4.0 s
Visual progress
Visual progress at 0 s0.0s
Visual progress at 1.3 s1.3s
Visual progress at 1.7 s1.7s
Visual progress at 2.2 s2.2s
Visual progress at 3.1 s3.1s
Visual progress at 4.1 s4.1s
Visual progress at 4.6 s4.6s
Visual progress at 4.9 s4.9s
FCP1.29s
LCP1.29s
VC854.90s
Long tasks
0.0s1.0s2.0s2.9s3.9s4.9s

Google Web Vitals

from run 2

Largest Contentful Paint

When the page main content is rendered, collected via the Largest Contentful Paint API. Read more about Largest Contentful Paint.

1.288 sLCP render time

Phase breakdown

  • TTFB404 ms
  • Resource load delay0 ms
  • Resource load duration0 ms
  • Element render delay884 ms

Element

Element type
<p>
Element id
mwRg
Size (w × h)
107256
Load time
0 ms
Style recalculation before LCP
4 recalculations touching 803 elements (196.097 ms) — the largest touched 791 elements (190.914 ms)

DOM path

body > div#mw-mf-viewport > div#mw-mf-page-center > main#content > div#bodyContent > div#mw-content-text > div:eq(0) > section#mwAQ > p#mwRg
LCP

The LCP element is highlighted in the screenshot. If nothing is highlighted the element was removed before the screenshot or the LCP API couldn't find it.

Cumulative Layout Shift

How much the page's content shifts as it loads, collected via the Cumulative Layout Shift API.

0.000cumulative layout shift score

No layout shifts were detected on this page.

Browser Metrics

Navigation Timing
Extra timings
User Timing marks
mwStartup2.147 s
mwCentralNoticeBanner4.582 s

Server timings

Timing data the server chose to expose through Server-Timing response headers on the main document — typically backend time, cache status or experiment flags.

Server timings

3 entries
NameDurationDescription
cache0 mshit-front
host0 mscp3070
co_id0 ms2826481135

Custom metrics collected through JavaScript

There are no custom configured scripts.

Extra metrics collected using scripting

There are no custom extra metrics from scripting.

Visual Elements3
LargestImagewikipedia-wordmark-en-25.svg
Display time1.300 s
Position (x, y)53, 16
Size (w × h)140 × 22
HTML snippet
<img src="/static/images/mobile/copyright/wikipedia-wordmark-en-25.svg" alt="Wikipedia" width="140" height="22" style="width: 8.75em; height: 1.375em;">
LargestImage preview
Heading
Display time4.667 s
Position (x, y)16, 212
Size (w × h)328 × 37
HTML snippet
<h1 id="firstHeading" class="firstHeading mw-first-heading"></h1>
LargestContentfulPaint
Display time4.667 s
Position (x, y)16, 449
Size (w × h)328 × 503
HTML snippet
<p id="mwRg"></p>

PageXray

How the page is built.

HTTP versionHTTP/2.0
Total requests39
Total domains5
Transfer size963.0 KB
Content size3.2 MB
Missing compression0
Cookies170 third-party

Main document

status 200 · 0 redirects

https://en.wikipedia.org/wiki/Sweden

HeaderValue
accept-ch
accept-rangesbytes
age11260
cache-controlprivate, s-maxage=0, max-age=0, must-revalidate, no-transform
content-encodinggzip
content-languageen
content-length248593
content-security-policyscript-src 'unsafe-eval' blob: 'self' meta.wikimedia.org *.wikimedia.org *.wikipedia.org *.wikinews.org *.wiktionary.org *.wikibooks.org *.wikiversity.org *.wikisource.org wikisource.org *.wikiquote.org *.wikidata.org *.wikifunctions.org *.wikivoyage.org *.mediawiki.org mediawiki.org wikimedia.org *.wmflabs.org *.wmcloud.org *.toolforge.org wss://*.toolforge.org *.jsdelivr.net unpkg.com cdnjs.cloudflare.com raw.githubusercontent.com *.github.com code.jquery.com cdn.mathjax.org use.typekit.net fonts.cdnfonts.com use.fontawesome.com i.ytimg.com rsms.me doi.org localhost https://localhost:* http://localhost:* wss://localhost:* ws://localhost:* *.google.com *.gstatic.com *.googleapis.com *.translate.yandex.net yastatic.net ya.ru radically.github.io cdn.sammdot.ca cdn.fontshare.com viaf.org publicai-proxy.alaexis.workers.dev iiif.archive.org api.flickr.com live.staticflickr.com api.anthropic.com api.openai.com api.publicai.co catalogo.pusc.it parsifal.urbe.it opac.sbn.it overpass-api.de api.openrouteservice.org archive.org *.openstreetmap.org *.waymarkedtrails.org *.thunderforest.com registry.ipe.wiki analytics.ipe.wiki qlever.dev app.goacoustic.com wikipedia-archive.ourworldindata.org api.inaturalist.org inaturalist-open-data.s3.amazonaws.com validator.w3.org db.onlinewebfonts.com fontlibrary.org 'unsafe-inline' auth.wikimedia.org; default-src 'self' data: blob: upload.wikimedia.org thumb.wikimedia.org https://commons.wikimedia.org meta.wikimedia.org *.wikimedia.org *.wikipedia.org *.wikinews.org *.wiktionary.org *.wikibooks.org *.wikiversity.org *.wikisource.org wikisource.org *.wikiquote.org *.wikidata.org *.wikifunctions.org *.wikivoyage.org *.mediawiki.org mediawiki.org wikimedia.org *.wmflabs.org *.wmcloud.org *.toolforge.org wss://*.toolforge.org *.jsdelivr.net unpkg.com cdnjs.cloudflare.com raw.githubusercontent.com *.github.com code.jquery.com cdn.mathjax.org use.typekit.net fonts.cdnfonts.com use.fontawesome.com i.ytimg.com rsms.me doi.org localhost https://localhost:* http://localhost:* wss://localhost:* ws://localhost:* *.google.com *.gstatic.com *.googleapis.com *.translate.yandex.net yastatic.net ya.ru radically.github.io cdn.sammdot.ca cdn.fontshare.com viaf.org publicai-proxy.alaexis.workers.dev iiif.archive.org api.flickr.com live.staticflickr.com api.anthropic.com api.openai.com api.publicai.co catalogo.pusc.it parsifal.urbe.it opac.sbn.it overpass-api.de api.openrouteservice.org archive.org *.openstreetmap.org *.waymarkedtrails.org *.thunderforest.com registry.ipe.wiki analytics.ipe.wiki qlever.dev app.goacoustic.com wikipedia-archive.ourworldindata.org api.inaturalist.org inaturalist-open-data.s3.amazonaws.com validator.w3.org db.onlinewebfonts.com fontlibrary.org en.wikibooks.org en.wikinews.org en.wikiquote.org en.wikisource.org en.wikiversity.org en.wikivoyage.org en.wiktionary.org www.mediawiki.org commons.wikimedia.org foundation.wikimedia.org incubator.wikimedia.org species.wikimedia.org wikimania.wikimedia.org www.wikidata.org www.wikifunctions.org auth.wikimedia.org; style-src 'self' data: blob: upload.wikimedia.org thumb.wikimedia.org https://commons.wikimedia.org meta.wikimedia.org *.wikimedia.org *.wikipedia.org *.wikinews.org *.wiktionary.org *.wikibooks.org *.wikiversity.org *.wikisource.org wikisource.org *.wikiquote.org *.wikidata.org *.wikifunctions.org *.wikivoyage.org *.mediawiki.org mediawiki.org wikimedia.org *.wmflabs.org *.wmcloud.org *.toolforge.org wss://*.toolforge.org *.jsdelivr.net unpkg.com cdnjs.cloudflare.com raw.githubusercontent.com *.github.com code.jquery.com cdn.mathjax.org use.typekit.net fonts.cdnfonts.com use.fontawesome.com i.ytimg.com rsms.me doi.org localhost https://localhost:* http://localhost:* wss://localhost:* ws://localhost:* *.google.com *.gstatic.com *.googleapis.com *.translate.yandex.net yastatic.net ya.ru radically.github.io cdn.sammdot.ca cdn.fontshare.com viaf.org publicai-proxy.alaexis.workers.dev iiif.archive.org api.flickr.com live.staticflickr.com api.anthropic.com api.openai.com api.publicai.co catalogo.pusc.it parsifal.urbe.it opac.sbn.it overpass-api.de api.openrouteservice.org archive.org *.openstreetmap.org *.waymarkedtrails.org *.thunderforest.com registry.ipe.wiki analytics.ipe.wiki qlever.dev app.goacoustic.com wikipedia-archive.ourworldindata.org api.inaturalist.org inaturalist-open-data.s3.amazonaws.com validator.w3.org db.onlinewebfonts.com fontlibrary.org 'unsafe-inline'; object-src 'none'; report-uri /w/api.php?action=cspreport&format=json; report-to csp-report-to-endpoint
content-typetext/html; charset=UTF-8
dateSun, 20 Sep 2026 11:21:52 GMT
last-modifiedSun, 20 Sep 2026 11:19:11 GMT
nel{ "report_to": "wm_nel", "max_age": 604800, "failure_fraction": 0.05, "success_fraction": 0.0}
report-to{ "group": "wm_nel", "max_age": 604800, "endpoints": [{ "url": "https://intake-logging.wikimedia.org/v1/events?stream=w3c.reportingapi.network_error&schema_uri=/w3c/reportingapi/network_error/1.0.0" }] }
reporting-endpointscsp-report-to-endpoint='/w/api.php?action=cspreport&format=json';
servermw-web.eqiad.main-5f96df4694-b9d2p
server-timingcache;desc="hit-front", host;desc="cp3070",co_id;desc="2826481135"
strict-transport-securitymax-age=106384710; includeSubDomains; preload
varyAccept-Encoding,X-Subdomain,Cookie,Authorization,User-Agent
x-analytics
x-cachecp3070 miss, cp3070 hit/23
x-cache-statushit-front
x-client-ip138.201.135.103
x-content-type-optionsnosniff
x-request-id67390595-851b-4e13-83c0-00c1d9056c99

Response codes

200
3794.9%
202
12.6%
302
12.6%

Requests and sizes per content type

8 types

Transfer size963.0 KB

  • image39.1%
  • javascript29.6%
  • html25.9%
  • css2.8%
  • svg2.2%
  • favicon0.19%
  • json0.19%
  • plain0.09%

Content size3.2 MB

  • html49.6%
  • javascript33.2%
  • image11.0%
  • css5.6%
  • svg0.45%
  • favicon0.08%
  • json0.01%

Requests38

  • svg39.5%
  • image28.9%
  • javascript15.8%
  • css5.3%
  • html2.6%
  • favicon2.6%
  • json2.6%
  • plain2.6%
ContentHeader SizeTransfer SizeContent SizeRequests
html0 b249.0 KB1.6 MB1
css0 b27.0 KB182.9 KB2
javascript0 b284.6 KB1.1 MB6
image0 b376.7 KB356.7 KB11
favicon0 b1.8 KB2.7 KB1
svg0 b21.1 KB14.6 KB15
json0 b1.8 KB288 B1
plain0 b903 B0 b1
Total0 b963.0 KB3.2 MB38

Data per domain

5 domains
DomainTotal download timeTransfer SizeContent SizeRequests
en.wikipedia.org5.471 s584.2 KB2.8 MB27
thumb.wikimedia.org1.129 s318.8 KB308.7 KB5
upload.wikimedia.org1.340 s55.9 KB46.7 KB5
auth.wikimedia.org186 ms1.5 KB254 B1
meta.wikimedia.org101 ms2.6 KB5.2 KB1

Expires & last-modified statistics

typeminmedianmax
Expires0 seconds4 weeks1 year
Last modified3 minutes9 weeks13 years

Requests loaded after onLoad event

12 requests

Includes requests done after load event end.

ContentTransfer SizeRequests
html0 b0
css0 b0
javascript4.1 KB2
image62.6 KB7
font0 b0
favicon1.8 KB1
plain903 B1
Total69.4 KB12

Requests loaded after onContentLoad

16 requests

Includes requests done after DOM content loaded.

ContentTransfer SizeRequests
html0 b0
css0 b0
javascript262.4 KB5
image62.6 KB7
font0 b0
favicon1.8 KB1
svg1.2 KB1
plain903 B1
Total328.8 KB16

CoverageProfile run

JavaScript and CSS coverage from the extra profile run made by --enableProfileRun, not from the timed iterations. For JS, Chrome tracks which blocks of each script actually ran: a byte is unused when the innermost block of code around it never ran. For CSS, Chrome records every selector that no element on the page matched during the iteration. Enable with --chrome.coverage on every run, or --enableProfileRun to keep the main run's timing metrics untouched. Unused bytes still cost network, parse and compile time for no benefit. Expand the section below for the full picture.

How is "unused" calculated?

sitespeed.io drives Chrome's V8 profiler and CSS rule tracker via the DevTools Protocol, the same machinery the DevTools Coverage panel uses. The two columns are populated by two different mechanisms.

JavaScript

Browsertime calls Profiler.startPreciseCoverage with detailed (block-level) mode at the start of the iteration and Profiler.takePreciseCoverage at the end. V8 returns nested ranges per function: an outer range covering the function body and inner ranges for sub-blocks (if/else, switch arms, ternaries). Each range has an execution count. A byte is "used" if the innermost range that covers it has count > 0, "unused" if it has count = 0, so we catch both functions that never ran AND dead branches inside functions that did.

CSS

Browsertime calls CSS.startRuleUsageTracking at the start of the iteration and CSS.stopRuleUsageTracking at the end. Chrome returns a flat list of rule-text ranges with a used flag: a rule is "used" if at least one element on the page matched it during the iteration. Both inline <style> blocks and external stylesheets are included.

What "this iteration" means

Coverage reflects only what executed during this run. Code behind a button click stays unused unless the iteration clicked the button. The collection window opens before navigation and closes when measure.stop() is reached, so the only way to count interactions is to drive them between measure.start() and measure.stop() inside a navigation script (pass a .js file as the input instead of a plain URL). Clicks, form fills and waits placed there all count toward "used". --preScript runs before the URL is loaded so it can't interact with the page being measured, and --postScript runs after coverage has already been collected, so neither helps here. Detailed coverage also tells V8 to skip some optimisations, which drifts timing metrics like LCP and TBT; that's why --enableProfileRun is the safer option for production measurement (it collects coverage in a separate iteration that doesn't count towards the medians).

JS total1.1 MB
JS unused441.4 KB
JS unused %40.5%
CSS total318.1 KB
CSS unused270.0 KB
CSS unused %84.9%

Where the bytes go

16 files · tile size is total bytes, tint is unused share

1.4 MB of script and style shipped, and 711.4 KB of it never ran on this page. The biggest win is load.php[scripts:ext.centralNotice.bannerHistoryLogger]: 955.1 KB delivered, 404.5 KB unused, and inside it jquery alone ships 69.8 KB of dead code.

load.php[scripts:ext.centralNotice.bannerHistoryLogger]955.1 KB · 42% unused
load.php[styles:ext.cite.parsoid.styles]176.3 KB · 79% unused
inline128.8 KB · 94% unused
load.php[startup]67.2 KB · 9% unused
load.php[scripts:ext.visualEditor.core.utils.parsing]26.9 KB · 87% unused
load.php[scripts:ext.gadget.WikiMiniAtlas]19.9 KB · 34% unused
inline14.9 KB · 4% unused
9 more files18.5 KB · 51% unused
Unused shareunder 40%40 to 70%over 70%Click a bundle marked ⤢ to see its modules.

Where the unused bytes live

first-party regex (.*wikipedia.*||.*wikimedia.*)
JS unused
First 441.4 KBThird 0 b
CSS unused
First 270.0 KBThird 0 b

JavaScript files

showing 7 of 7 URLs (from 10 scripts), sorted by unused bytes
URLTotalUsedUnusedUnused %
load.php[scripts:ext.centralNotice.bannerHistoryLogger]955.1 KB550.5 KB404.5 KB
42.4%
76 modules in this bundle, by unused bytes
ModuleVersionTotalUsedUnusedUnused %
jquery16rou137.4 KB67.6 KB69.8 KB
50.8%
ext.wikimediaEvents1yvhb57.8 KB19.6 KB38.3 KB
66.2%
mediawiki.apipwy0p27.1 KB4.9 KB22.2 KB
82.0%
ext.uls.interface1em5547.4 KB25.4 KB21.9 KB
46.3%
mobile.startup14ueh60.3 KB39.6 KB20.7 KB
34.4%
skins.minerva.scriptsn2w9g56.7 KB40.2 KB16.5 KB
29.1%
ext.testKitchenm6xrf32.5 KB18.9 KB13.6 KB
41.8%
ext.centralNotice.display1jgtq30.5 KB18.5 KB12.0 KB
39.4%
mobile.initf824a18.8 KB7.3 KB11.5 KB
61.3%
oojs1797x15.0 KB3.6 KB11.4 KB
76.2%
mediawiki.template.mustache1niba12.1 KB1.6 KB10.5 KB
86.5%
mediawiki.util1pwbb16.4 KB6.6 KB9.9 KB
60.1%
mediawiki.page.ready1nlsh16.8 KB7.0 KB9.8 KB
58.4%
ext.navigationTiming18ja510.8 KB1.4 KB9.3 KB
86.6%
mediawiki.DateFormattergv7yr13.2 KB4.2 KB9.0 KB
68.4%
mediawiki.jqueryMsgarc6u29.8 KB22.0 KB7.8 KB
26.2%
mediawiki.page.watch.ajax1mh2f9.6 KB1.9 KB7.7 KB
79.9%
mmv.bootstrap1h2p128.5 KB21.3 KB7.2 KB
25.3%
ext.quicksurveys.libq621v14.3 KB7.6 KB6.7 KB
47.1%
ext.eventLogging.metricsPlatformadrwj14.6 KB9.0 KB5.6 KB
38.5%
jquery.textSelection16q5k5.8 KB287 B5.6 KB
95.2%
ext.wikimediaEvents.testKitchen1pb2h6.1 KB1.5 KB4.6 KB
75.5%
mediawiki.Title11zzw10.2 KB6.0 KB4.2 KB
41.0%
ext.centralNotice.kvStore1ggbc6.8 KB2.7 KB4.1 KB
60.0%
ext.centralauth.ForeignApi4lgeh4.6 KB776 B3.9 KB
83.7%
jquery.uls.data66u8843.3 KB39.5 KB3.8 KB
8.8%
mediawiki.base14qhp28.5 KB24.8 KB3.7 KB
13.1%
ext.eventLogging1xqug28.0 KB24.5 KB3.5 KB
12.5%
ext.cite.ux-enhancements1bohi4.9 KB1.5 KB3.4 KB
69.4%
mw.cx.SiteMapper1fopq4.3 KB1.0 KB3.3 KB
76.6%
mediawiki.language11hcb8.7 KB5.4 KB3.3 KB
38.2%
ext.centralNotice.bannerHistoryLoggert5uro4.0 KB807 B3.2 KB
80.1%
ext.tmh.player1rhlj6.5 KB3.7 KB2.8 KB
42.9%
ext.urlShortener.toolbar1dk5r3.8 KB1.1 KB2.7 KB
70.9%
mediawiki.user1lcpm4.2 KB1.7 KB2.4 KB
58.7%
ext.checkUser.clientHints7tpv03.0 KB635 B2.4 KB
79.3%
mediawiki.String1xixe2.4 KB543 B1.9 KB
78.0%
ext.centralNotice.largeBannerLimit1tsy72.2 KB479 B1.8 KB
78.9%
mediawiki.routerx9r1o2.4 KB761 B1.7 KB
69.3%
ext.cx.entrypoints.languagesearcher.v21ipyw3.1 KB1.6 KB1.6 KB
50.2%
jquery.client1n4yo3.3 KB1.8 KB1.5 KB
44.9%
ext.wikimediaCustomizations.donoru2ec82.5 KB1.0 KB1.5 KB
59.6%
ext.uls.webfonts198622.0 KB663 B1.4 KB
67.8%
mediawiki.ForeignApi.corepb72f2.2 KB863 B1.3 KB
61.1%
ext.centralNotice.startUptrejq3.3 KB2.0 KB1.3 KB
39.3%
ext.wikimediaCustomizations.donorAccountCreationnzrmw2.6 KB1.4 KB1.3 KB
48.6%
mediawiki.libs.pluralruleparser1utt83.6 KB2.4 KB1.2 KB
34.3%
mediawiki.template1blsn1.5 KB359 B1.2 KB
77.4%
mediawiki.visibleTimeoutehbob1.5 KB434 B1.1 KB
71.5%
mediawiki.cookieq6bh03.2 KB2.3 KB892 B
27.6%
mediawiki.storagednxpi2.9 KB2.1 KB890 B
29.6%
ext.centralNotice.geoIP1g16w1.5 KB850 B698 B
45.1%
mw.externalguidance.initxfoyw1.4 KB751 B671 B
47.2%
ext.centralNotice.impressionDiet2jcqc2.7 KB2.1 KB655 B
23.7%
ext.uls.rewrite.entrypoints1peyz1.8 KB1.2 KB607 B
32.7%
jquery.spinnerm5xio827 B234 B593 B
71.7%
ext.phonos.init1mtl8962 B512 B450 B
46.8%
mediawiki.page.media1h6ho949 B501 B448 B
47.2%
ext.uls.preferences17lrh1.1 KB645 B445 B
40.8%
ext.relatedArticles.readMore.bootstrap4dy0q961 B573 B388 B
40.4%
ext.centralauth.centralautologin1rxda1.3 KB961 B325 B
25.3%
ext.popups1ayph735 B486 B249 B
33.9%
ext.centralNotice.legacySupport1qdcf453 B254 B199 B
43.9%
ext.cx.eventlogging.campaigns48624347 B187 B160 B
46.1%
ext.echo.centralauth19vyg340 B220 B120 B
35.3%
wikibase.databox.fromWikidatalwf59709 B640 B69 B
9.7%
mediawiki.experiments1jfeg780 B756 B24 B
3.1%
ext.centralNotice.choiceData1kuli30.8 KB30.8 KB4 B
0.0%
ext.cx.model1wwuh224 B224 B0 b
0.0%
ext.quicksurveys.init1b0cn345 B345 B0 b
0.0%
ext.scribunto.logs1dyyv141 B141 B0 b
0.0%
sitedzx9s2.1 KB2.1 KB0 b
0.0%
jquery.spinner.styles1ln052.2 KB2.2 KB0 b
0.0%
mediawiki.ForeignApirqcii72 B72 B0 b
0.0%
mediawiki.cldr13x6e350 B350 B0 b
0.0%
mobile.codex.styles1frpm41.3 KB41.3 KB0 b
0.0%
load.php[scripts:ext.visualEditor.core.utils.parsing]26.9 KB3.5 KB23.3 KB
86.9%
4 modules in this bundle, by unused bytes
ModuleVersionTotalUsedUnusedUnused %
ext.visualEditor.targetLoaderatgms23.0 KB2.4 KB20.5 KB
89.4%
ext.visualEditor.core.utils.parsingipi2f3.3 KB800 B2.5 KB
76.5%
ext.visualEditor.vepoyn0303 B124 B179 B
59.1%
ext.visualEditor.track14ulv295 B192 B103 B
34.9%
load.php[scripts:ext.gadget.WikiMiniAtlas]19.9 KB13.2 KB6.7 KB
33.7%
2 modules in this bundle, by unused bytes
ModuleVersionTotalUsedUnusedUnused %
ext.gadget.WikiMiniAtlasgjobl18.6 KB12.1 KB6.5 KB
35.2%
ext.gadget.switcheregrcs1.3 KB1.1 KB169 B
12.6%
load.php[startup]67.2 KB61.0 KB6.2 KB
9.2%
(inline) 4 scripts14.9 KB14.4 KB543 B
3.6%
https://en.wikipedia.org/wiki/Special:CentralAutoLogin/start?useformat=mobile&type=script&usesul3=1254 B155 B99 B
39.0%
https://meta.wikimedia.org/w/index.php...a.org/w/index.php5.2 KB5.2 KB0 b
0.0%

CSS files

showing 9 of 9 URLs (from 13 stylesheets), sorted by unused bytes
URLTotalUsedUnusedUnused %
load.php[styles:ext.cite.parsoid.styles]176.3 KB37.2 KB139.1 KB
78.9%
(inline stylesheet) 5 stylesheets128.8 KB7.2 KB121.6 KB
94.4%
load.php[styles:site.styles]6.6 KB955 B5.7 KB
85.9%
TemplateStyles:r13744274042.3 KB466 B1.8 KB
80.1%
TemplateStyles:r13586202341.3 KB135 B1.2 KB
89.8%
TemplateStyles:r10432823172.2 KB1.7 KB570 B
24.9%
TemplateStyles:r1368532237303 B182 B121 B
39.9%
TemplateStyles:r1156832818295 B295 B0 b
0.0%
TemplateStyles:r88604748845 B45 B0 b
0.0%

What to do about unused bytes

one iteration is a sample, not a verdict

A high unused-% on one run means this iteration loaded code that didn't get exercised, typical on first-load journeys before any user interaction. Drive the real flow by passing a navigation script as the input instead of a plain URL, with clicks and form fills placed between measure.start() and measure.stop(); anything in that window counts toward "used". The advice below is for code that's still unused after a representative run.

JavaScript

  • Route-split and lazy-load below-the-fold features with dynamic import(). Bundlers turn the import boundary into a separate chunk.
  • Audit big bundles for dead exports, legacy polyfills, and feature flags that no longer ship; most modern bundlers tree-shake but only when imports are precise.
  • Question third-party scripts. Tag managers, analytics SDKs and A/B test loaders often ship far more than the page uses and dominate the third-party column above.
  • Move non-critical scripts to defer or async so the parser doesn't block on code the page doesn't need yet.

CSS

  • Strip selectors no shipped HTML matches: PurgeCSS, build-time scoping in your component framework, or your CSS-in-JS extractor.
  • Drop legacy browser fallbacks if your target floor has moved (vendor prefixes, IE hacks, old flexbox syntax).
  • Split route- or component-specific CSS so the home page doesn't carry the checkout's styles.
  • Inline the critical-path CSS (above-the-fold) and lazy-load the rest with media= tricks or rel="preload" swaps.

CPU

load.php[startup] is responsible for 52% of blocking time
705 ms of 1367 ms total. Defer it, replace it with a lighter alternative, or move its work off the main thread to recover most of your TBT.

Long tasks

Tasks ≥ 50 ms blocking the main thread, collected via the Long Task API.

TBT1.490 s
Max potential input delay527 ms
Total long tasks14
Total time2.558 s
Last task at4.704 s
Before first paint468 ms2 tasks
Before FCP468 ms2 tasks
Before LCP468 ms2 tasks
After load1.749 s9 tasks

Long Animation Frames

A long animation frame (LOAF) is a frame that took ≥ 50 ms from input to the next paint. The part beyond the threshold is blocking time, the number that hurts Interaction to Next Paint and Total Blocking Time. Break long tasks up (scheduler.yield(), smaller chunks) or move the work off the main thread. Read more about the Long Animation Frames API.

Long animation frames12showing the 10 with the most blocking time
Blocking time2.032 sacross all long frames — what hurts INP and TBT
Forced style & layout112.3 msscripts reading layout mid-frame
Blocking before LCP292.2 msdelaying the largest paint — fix these first
Blocking after load1.398 safter the load event — didn't delay page load

What to fix first

ScriptFramesTime runningBlocking (share by run time)Forced style & layoutTriggered by
load.php[startup]4864.7 ms704.9 ms73.4 mstimer or animation callback
load.php[scripts:ext.centralNotice.bannerHistoryLogger]5871.7 ms658.1 ms38.9 mstimer or animation callback
inline script in the document19.4 ms3.8 msscript tag

A frame's blocking time is split between its scripts by their share of the frame's work, capped at each script's own run time — blocking from work no script owns (HTML parsing, browser internals) stays unattributed. The per-script blocking view below uses the same attribution.

Long animation frame #1 · 578.7 msat 3.326 s · after load
blocking 502.8 ms
  • Scripts & other work553.8 ms
  • Animation callbacks24.2 ms
  • Style & layout0.7 ms
  • Render0 ms
1 script ran during this frame
Ran for
527.8 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 388273 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Long animation frame #2 · 370.8 msat 2.587 s · after load
blocking 318.6 ms
  • Scripts & other work277.9 ms
  • Animation callbacks78.1 ms
  • Style & layout14.8 ms
  • Render0 ms
2 scripts ran during this frame
Ran for
275.5 ms
Started by
IdleRequestCallback
How it started
timer or animation callback
Source function
doPropagation
Position in source
character 4301 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
78 ms
Started by
FrameRequestCallback
How it started
timer or animation callback
Source function
flushCssBuffer
Position in source
character 3227 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Long animation frame #3 · 730.8 msat 475.7 ms · before LCP
blocking 292.2 ms
  • Scripts & other work728.4 ms
  • Animation callbacks2.3 ms
  • Style & layout0.1 ms
  • Render0 ms
1 script ran during this frame
Ran for
9.4 ms
Queued before running
2.9 ms
How it started
script tag
Long animation frame #4 · 338.3 msat 3.964 s · after load
blocking 255.8 ms
  • Scripts & other work44.1 ms
  • Animation callbacks272.2 ms
  • Style & layout22 ms
  • Render0 ms
3 scripts ran during this frame · forced style & layout 73.4 ms
Ran for
11.6 ms
Started by
IdleRequestCallback
How it started
timer or animation callback
Source function
doPropagation
Position in source
character 4301 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
11.5 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 388273 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
272.1 ms
Forced style and layout
73.4 ms
Started by
FrameRequestCallback
How it started
timer or animation callback
Source function
flushCssBuffer
Position in source
character 3227 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Long animation frame #5 · 283.3 msat 1.523 s · before load
blocking 213.6 ms
  • Scripts & other work168.2 ms
  • Animation callbacks115 ms
  • Style & layout0.1 ms
  • Render0 ms

The browser did not report which script was responsible for this frame — typically its own style/layout work, or a cross-origin script it will not name.

Long animation frame #6 · 198.2 msat 1.870 s · before load
blocking 121.2 ms
  • Scripts & other work165.9 ms
  • Animation callbacks30.9 ms
  • Style & layout1.4 ms
  • Render0 ms

The browser did not report which script was responsible for this frame — typically its own style/layout work, or a cross-origin script it will not name.

Long animation frame #7 · 151.2 msat 4.704 s · after load
blocking 101.2 ms
  • Scripts & other work151.2 ms
  • Animation callbacks0 ms
  • Style & layout0 ms
  • Render0 ms
1 script ran during this frame
Ran for
150.9 ms
Started by
IdleRequestCallback
How it started
timer or animation callback
Source function
flushWrites
Position in source
character 19327 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Long animation frame #8 · 142.8 msat 3.163 s · after load
blocking 90.5 ms
  • Scripts & other work134 ms
  • Animation callbacks8.8 ms
  • Style & layout0 ms
  • Render0 ms
1 script ran during this frame · forced style & layout 8.6 ms
Ran for
131.5 ms
Forced style and layout
8.6 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 388273 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Long animation frame #9 · 185.9 msat 4.314 s · after load
blocking 67.5 ms
  • Scripts & other work183.5 ms
  • Animation callbacks2.4 ms
  • Style & layout0 ms
  • Render0 ms
2 scripts ran during this frame · forced style & layout 30.3 ms
Ran for
43.6 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 388273 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
115.1 ms
Forced style and layout
30.3 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 388273 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Long animation frame #10 · 150.6 msat 2.996 s · after load
blocking 61.2 ms
  • Scripts & other work81.6 ms
  • Animation callbacks45.2 ms
  • Style & layout23.8 ms
  • Render0 ms
3 scripts ran during this frame
Ran for
32.4 ms
Started by
IdleRequestCallback
How it started
timer or animation callback
Source function
doPropagation
Position in source
character 4301 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
42.2 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 388273 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
44.2 ms
Started by
FrameRequestCallback
How it started
timer or animation callback
Source function
flushCssBuffer
Position in source
character 3227 into the file (locate it via DevTools → Performance → the Long Animation Frames track)

Blocking time per script (browser-reported)

How much each script blocked the main thread, derived from the Long Animation Frame API. Each frame's blocking time is split between its scripts by their share of the frame's work, capped at each script's own run time — blocking from work no script owns (HTML parsing, browser internals) is not attributed (older data credits the script that started the frame). The closest answer to "which script should I fix to improve TBT" the platform exposes.

Top scripts blocking the main thread

3 of 3 scripts
load.php[startup]
705 ms · 7 frames · worst 248 ms
inline script in the document
4 ms · 1 frame · worst 4 ms

Blocking time per script (trace)

Total Blocking Time attributed per script from the Chrome trace: every main-thread task longer than 50 ms blocks input for the remainder, and each blocking task is credited to the script whose own code ran the longest during that task.

TBTNaN s
Blocking tasks18
TBT before LCP386.1 ms3 tasks

What kind of work blocked

mostly style & layout · 763 ms total
Style & layout436.6 ms57.2%
Parsing HTML & CSS245.0 ms32.1%
Paint & composite67.3 ms8.8%
Garbage collection11.9 ms1.6%
Parsing & compiling JavaScript1.9 ms0.2%
Style & layout (57%): usually a large DOM, expensive CSS selectors or JavaScript forcing synchronous layout. See Forced reflows · Forced layout per script · Slowest CSS selectors (Rendering tab) · Style invalidations (Rendering tab)
Parsing HTML & CSS (32%): reading the HTML document. A smaller document parses faster.

Top scripts blocking the main thread

3 of 3 scripts

Where the time went

All main-thread work during the full page load, not just the share that blocked input. Calculated from the Chrome trace.

Categories

4.500 s total
Running JavaScript2.012 s44.7%
Other browser work (scheduling)803 ms17.8%
Parsing HTML & CSS749 ms16.6%
Style & layout676 ms15.0%
Paint & composite217 ms4.8%
Garbage collection25 ms0.6%
Parsing & compiling JavaScript18 ms0.4%
What do these categories mean?
Parsing HTML & CSSparseHTML
Reading the HTML and CSS and building the page structure. Grows with document size — a big server-rendered page costs more here.
Style & layoutstyleLayout
Working out which CSS rules apply and where every element goes on the page. Grows with DOM size and selector complexity.
Parsing & compiling JavaScriptscriptParseCompile
Parsing and compiling JavaScript before it can run — the cost of shipping bytes of JS, even unused ones.
Running JavaScriptscriptEvaluation
Running JavaScript: event handlers, timers, promise callbacks and script execution.
Paint & compositepaintCompositeRender
Painting pixels and assembling layers into the frames you see on screen.
Garbage collectiongarbageCollection
Reclaiming memory JavaScript no longer uses. A lot of it means allocation-heavy code.
Other browser work (scheduling)other
Chrome’s own task management: per-task overhead and thousands of sub-millisecond scheduler ticks — not page work you can attribute or optimize away. On this page 796 ms of it is this per-task bookkeeping (RunTask self time in the trace).

CPU time per script

CPU time per moduleProfile run

Main-thread CPU time attributed to the individual modules inside concatenated JavaScript bundles (MediaWiki ResourceLoader), so a heavy bundle can be traced to the modules that actually cost the time.

The data comes from the extra profile run, not from the timed iterations.

ModuleVersionSelf time
jquery16rou805.1 ms
ext.centralNotice.startUptrejq8.5 ms
mediawiki.storagednxpi8.1 ms
ext.wikimediaEvents1yvhb6.6 ms
ext.navigationTiming18ja52.9 ms
skins.minerva.scriptsn2w9g2.2 ms
ext.testKitchenm6xrf0.1 ms
(rest of the bundle, not tied to one module)341.0 ms

Slowest JS functions

The functions where main-thread JavaScript time was actually spent, sampled by Chrome's JavaScript profiler. Self time is spent in the function itself; total time includes the functions it called. For loader/dispatcher functions whose total dwarfs their self time, the runs line shows the top functions and modules (up to five, ≥ 1 ms) the total was actually spent running.

Functions by self time

15 of 50 functions
FunctionWhereSelf timeTotal time
setAttributeBrowser internal (not your code)123.1 ms123.1 ms
flushWrites
runs: load.php[startup] (20.9 ms)
load.php[startup]122.7 ms143.6 ms
querySelectorAllBrowser internal (not your code)117.8 ms117.8 ms
(anonymous)load.php[scripts:ext.centralNotice.bannerHistoryLogger]74.5 ms74.5 ms
find
runs: querySelectorAll (105.8 ms), load.php[scripts:ext.centralNotice.bannerHistoryLogger] (17.3 ms), getElementsByTagName (4.9 ms), RegExp: ^[\x20\t\r\n\f]+|((?:^|[^\\])(?:\\.)*)[\x20\t\r\n\f]+$ (1.2 ms)
load.php[scripts:ext.centralNotice.bannerHistoryLogger]65.2 ms194.4 ms
runScript
runs: load.php[scripts:ext.centralNotice.bannerHistoryLogger] (417.6 ms)
load.php[startup]57.2 ms639.8 ms
insertBeforeBrowser internal (not your code)52.1 ms52.1 ms
replaceChildBrowser internal (not your code)46.7 ms46.7 ms
require
runs: load.php[scripts:ext.centralNotice.bannerHistoryLogger] (25.8 ms), load.php[startup] (4.3 ms)
load.php[startup]40.7 ms79.1 ms
appendChild
runs: (anonymous) (3.1 ms)
Browser internal (not your code)34.4 ms37.5 ms
initTabsScrollPosition
runs: load.php[scripts:ext.centralNotice.bannerHistoryLogger] (3.5 ms)
load.php[scripts:ext.centralNotice.bannerHistoryLogger]31.2 ms34.7 ms
t
runs: load.php[scripts:ext.centralNotice.bannerHistoryLogger] (275.2 ms)
load.php[scripts:ext.centralNotice.bannerHistoryLogger]30.2 ms254.8 ms
setTimeoutBrowser internal (not your code)29.9 ms29.9 ms
removeAttributeBrowser internal (not your code)29.9 ms29.9 ms
(anonymous)
runs: after (12.0 ms)
load.php[scripts:ext.centralNotice.bannerHistoryLogger]27.4 ms39.9 ms

TimersProfile run

How much setTimeout/setInterval work the page runs, credited to the script that scheduled each timer. Many zero-delay timers mean work sliced into a machine-gun of tiny tasks; repeating timers are polling.

Timers set58
Times fired56
Fire time1.028 s
Zero-delay timers53
Repeating timers0
Zero-delay slicing: jquery split work into 51 back-to-back tasks costing 1012 ms. Consider batching the work or moving it to requestIdleCallback or a worker.

Timer cost by script

3 scripts
load.php[scripts:ext.centralNotice.bannerHistoryLogger]
830 ms · set 57 times · fired 43 times
load.php[startup]
185 ms · set 1 time · fired 12 times

The timers, by where they were set

top 7 by fire time
Set byDelayTypeTimes setTimes firedFire time
jquery0 msonce51511012.1 ms
jquery0 msonce117.2 ms
SafeStorage in mediawiki.storage2000 msonce225.3 ms
ext.navigationTiming0 msonce112.9 ms
requestUpdate in load.php[startup]:222000 msonce110.5 ms
run in ext.wikimediaEvents60000 msonce100.0 ms
setActive in ext.wikimediaEvents100000 msonce100.0 ms

Forced reflows

A forced reflow happens when JavaScript reads a layout-triggering property (offsetTop, getBoundingClientRect, …) inside a handler, forcing the browser to synchronously recompute layout. The scripts below caused most of the page's reflows. Fix them in priority order.

Scripts causing reflows

8 reflows ≥ 2 ms across 2 scripts
load.php[startup]
73 ms · 2 reflows · worst 71 ms

Forced layout per script

Each long animation frame reports how much time each script spent forcing synchronous style and layout, i.e. JavaScript reading layout-triggering properties mid-execution. Same actionable answer as forced reflows above but measured directly by the browser instead of inferred from the trace.

Scripts forcing layout

2 of 2 scripts

First vs third party CPU time

Main-thread CPU time from the Chrome trace split by domain. First party is wikipedia.org.

First party1.965 s
Third party4 ms
Domains1

Non-composited animations

Animations that fell back from the compositor to the main thread, blocking each frame instead of running on the GPU.

Why they could not be composited

1 animation
  • animation has no visible change

The reason decides the action: “animation has no visible change” means Chrome skipped compositing because nothing visible moves — harmless. Property-related reasons mean the keyframes animate something other than transform or opacity.

Want to dig deeper? Download the Chrome trace and drag-and-drop it into Performance in DevTools.