Run 2 summary

https://www.mediawiki.org/wiki/Download

Tested 2026-08-24 23:21:37 using Chrome 151.0.7922.75 (runtime settings)

SummaryWaterfallMetricsRenderingCoachPageXrayCPU

Summary

Google Web Vitals

403 msTTFB
1.468 sLargest Contentful Paint
0.583Cumulative Layout Shift
882 msTotal Blocking Time

Loading

812 msFirst Paint
2.992 sFully Loaded
357 msMax Potential FID

Page weight & requests

637.8 KBTotal transfer size
2.6 MBTotal content size
25Requests

CPU

10Long tasks
3.823 sLast long task at

Visual progress

833 msFirst Visual Change
1.304 sSpeed Index
1.467 sVisual Complete 85%
2.367 sVisual Complete 99%
2.367 sLast Visual Change
Screenshot
Run 2 · after page complete

Waterfall

First paintFCPLCPDOMContentLoadedDOM interactiveLoadRender-blockingRedirectError

Rendering

Run 2
0.000 s
0s1s2s

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

12 frames

Use --filmstrip.showAll to show all filmstrips.

Frame at 0 ms
0 ms
0 %
Frame at 700 ms
700 ms
0 %
Frame at 900 ms
900 ms
36 %
Frame at 1.000 s
1.000 s
38 %
Frame at 1.500 s
1.500 s
89 %
Frame at 1.600 s
1.600 s
90 %
Frame at 1.700 s
1.700 s
90 %
Frame at 1.800 s
1.800 s
90 %
Frame at 2.100 s
2.100 s
90 %
Frame at 2.200 s
2.200 s
98 %
Frame at 2.300 s
2.300 s
98 %
Frame at 2.400 s
2.400 s
100 %

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

Visual instability

94.93 % of pixels ever changed · 0 % 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 shown12
Partial0
Dropped7
Effective FPS5.1
Longest gap610 msat 2.339 s

Why was rendering delayed?

Rendering was not meaningfully delayed. First paint landed at 812 ms on a 403 ms first byte; the 2 render-blocking requests were done by 623 ms and the remaining ~189 ms is style and layout work (60 ms of it measured style recalculation). The largest paint followed at 1.468 s.

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).

Style recalculation is not holding up your paint. 60 ms of restyling before the page painted, 7.4 % of the time to First Contentful Paint. Nothing here needs attention.

Before first contentful paint

Recalculations3
Elements94
Total time59.721 ms
Largest recalculation92 elements · 57.211 ms

Before largest contentful paint

Recalculations15
Elements561
Total time164.344 ms
Largest recalculation420 elements · 94.63 ms

The recalculation work before first paint is 7.4 % of the time to First Contentful Paint.

Render blocking requests

3 requests · 59.3 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 dashed line is FCP, the clock ends at LCP); the gap after the bars is style and layout work.

RequestWhen it loadedTransferDownload
document
www.mediawiki.org · TTFB 403 ms
491 ms
23.7 KB490 ms
ext.discussionTools.init.styles + 18 more modulesblocking
css · load.php styles batch · www.mediawiki.org
166 ms
37.1 KB166 ms
site.stylesblocking
css · load.php styles batch · www.mediawiki.org
165 ms
1.6 KB165 ms
startuppotentially blocking
javascript · load.php startup · www.mediawiki.org
208 ms
20.7 KB208 ms
0367 ms1.101 sFCP 812 msLCP 1.468 s

Style invalidations

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. 188 style recalculations and 1 182 layout invalidations fired after first paint, on a page the user was already looking at. The biggest driver is attribute class (23×). Start with the script under "Scripts causing invalidations" that keeps triggering it.

Style recalculations193188 after first paint
Layout invalidations1 2991 182 after first paint

Changes that keep invalidating

top 15
  • attribute: class23×
  • attribute: id
  • attribute: role
  • attribute: aria-expanded
  • pseudo: disabled
  • pseudo: enabled
  • attribute: style
  • attribute: title
  • pseudo: first-child
  • attribute: disabled
  • class: content
  • class: touch-events
  • class: ext-discussiontools-init-ready
  • class: minerva-animations-ready
  • pseudo: only-child

Invalidation reasons

split at first paint

Between first and largest paint

Invalidations while the largest paint was still pending, so these delayed it.

ReasonStyle recalculationsLayout
A node was inserted into the page26
An element entered layout917
An element left layout1
Unknown4
An element's size changed4
An SVG element changed1

After the largest paint

Churn on the fully rendered page: wasted work and possible jank, but no paint delay.

ReasonStyle recalculationsLayout
A node was inserted into the page57
Related style rule56
A stylesheet rule changed37
Attribute6
A pseudo-class state changed (:hover, :focus, …)2
JavaScript changed an inline styleSet a class instead of writing element.style, so the browser can batch the work.2
An animation updated stylesAnimate transform and opacity so the compositor can run it off the main thread.1
An @keyframes rule changed1
An element entered layout213
An element left layout15
A style change forced layout14
Unknown6
An element's size changed6
An SVG element changed1

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 page4
A stylesheet rule changed1
An element entered layout110
An element left layout3
Unknown3
An element's size changed1

Scripts causing invalidations

top 2

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.

What to fix first

Performance advice

86
10 warnings3 info
infoAdd decoding="async" to non-critical imagesdecodingAsync

The page has 5 images (out of 5) 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(0)Avoid CPU Long TaskslongTasks

The page has 10 CPU long tasks with the total of 1.440 s. The total blocking time is 882 ms and 1 long task before first contentful paint with total time of 108 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
warn(0)Serve images in modern formats (AVIF, WebP)modernImageFormats

The page ships 1 image (out of 1) 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)Total JavaScript size shouldn't be too bigjavascriptSize

The total JavaScript transfer size is 555 kB and the uncompressed size is 2.3 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://www.mediawiki.org/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=minerva20.7 KB62.6 KB
https://www.mediawiki.org/w/load.php...ki.org/w/load.php9.4 KB26.9 KB
https://www.mediawiki.org/w/load.php...ki.org/w/load.php372.4 KB1.5 MB
https://auth.wikimedia.org/metawiki/wiki/Special:CentralAutoLogin/checkLoggedIn...gin/checkLoggedIn1.5 KB254 B
https://www.mediawiki.org/w/load.php...ki.org/w/load.php138.1 KB596.7 KB
warn(75)Lazy-load below-the-fold imageslazyLoadingImages

The page has 1 below-the-fold image 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(80)Don't scale images in the browseravoidScalingImages

The page has 2 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(80)Avoid extra requests by setting cache headerscacheHeaders

The page has 2 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 1.5 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(80)Don't use private headers on static contentprivateAssets

The page has 3 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 19 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
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
infoMake each CSS response smalloptimalCssSize

https://www.mediawiki.org/w/load.php?lang=en&modules=ext.discussionTools.init.styles%7Cext.dismissableSiteNotice.styles%7Cext.pygments%2Ctranslate%7Cext.translate.edit.documentation.styles%7Cext.translate.tag.languages%7Cext.wikimediamessages.styles%7Cmediawiki.hlist%7Cmediawiki.ui.button%7Cmediawiki.widgets.styles%7Cmobile.init.styles%7Coojs-ui-core.icons%2Cstyles%7Coojs-ui.styles.indicators%7Cskins.minerva.codex.styles%7Cskins.minerva.content.styles.images%7Cskins.minerva.icons%2Cstyles%7Cwikibase.client.init&only=styles&skin=minerva size is 38 kB (37959) and that is bigger than the limit of 25 kB. Try to keep each CSS response under 25 kB.

Render-blocking CSS holds up the first paint until it has fully downloaded, parsed and applied, so smaller CSS files mean a faster start. Split your CSS into a small critical bundle inlined or eagerly loaded, with the rest lazy-loaded.

Offenders
URLTransferContent
https://www.mediawiki.org/w/load.php...ki.org/w/load.php37.1 KB307.4 KB
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(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://www.mediawiki.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

72
1 error3 info
error(0)Cumulative Layout ShiftcumulativeLayoutShift

You have a poor cumulative layout shift score (0.5825). It is in the Google Web Vitals poor range, with a shift higher than 0.25. You should manually check the filmstrip or video and check if it will affect the user.

Cumulative Layout Shift measures the sum total of all individual layout shift scores for unexpected layout shift that occur. The metric is measuring visual stability by quantify how often users experience unexpected layout shifts. It is one of Google Web Vitals.

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 22 responses that sets both a max-age and expires header. There are 25 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://www.mediawiki.org/wiki/Download has a header content-security-policy that is 4540 characters long. https://www.mediawik...ki.org/w/load.php has a header sourcemap that is 1237 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.

TitleDownload - MediaWikiThe document title, shown in the browser tab and used by search results.
GeneratorMediaWiki 1.47.0-wmf.16The tool or CMS that generated the HTML, from the page generator meta tag.
Layout viewport360 × 2935 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 elements764Total HTML elements. Fewer means less for the browser to style, lay out and paint.
Avg DOM depth11How deeply elements are nested on average.
Max DOM depth17The deepest nesting on the page. Deep branches cost more style recalculation.
Iframes0No embedded documents on this page.
Script tags7Number 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 storage1.1 MBData 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://www.mediawiki.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

Visual Metrics

Visual milestones

all times from navigation start
Speed Index1.30 show quickly the page looked done
First Visual Change0.83 sfirst paint reaches the screen
Last Visual Change2.37 sscreen stops changing · 1.53 s after first
nothing painted yet
≥85%
≥95% rendered
First Visual Change0.83 s
1.47 sVisual Complete 85%
Visual Complete 95%2.17 s
Visual Complete 99% · Last Visual Change2.37 s
Visual Readiness1.53 s· first to last change
00.5 s1.0 s1.5 s2.0 s
Visual progress
Visual progress at 0 s0.0s
Visual progress at 0.9 s0.9s
Visual progress at 1 s1.0s
Visual progress at 1.6 s1.6s
Visual progress at 1.7 s1.7s
Visual progress at 2.1 s2.1s
Visual progress at 2.2 s2.2s
Visual progress at 2.4 s2.4s
FCP0.81s
LCP1.47s
VC851.47s
Long tasks
0.0s0.5s1.0s1.4s1.9s2.4s

Google Web Vitals

Largest Contentful Paint

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

1.468 sLCP render time

Phase breakdown

  • TTFB403 ms
  • Resource load delay0 ms
  • Resource load duration0 ms
  • Element render delay1.065 s

Element

Element type
<ul>
Size (w × h)
89253
Load time
0 ms
Style recalculation before LCP
15 recalculations touching 561 elements (164.344 ms) — the largest touched 420 elements (94.63 ms)

DOM path

body > div#mw-mf-viewport > div#mw-mf-page-center > main#content > div#bodyContent > div#mw-content-text > div:eq(1) > section#mf-section-0 > div:eq(0) > ul
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.

0.583cumulative layout shift score

One shift is 95% of your 0.583 CLS. div#bodyContent moved at 2.110 s. Reserve space for whatever renders into that spot, a fixed height or an aspect-ratio box, so later content stops pushing the page around.

Elements that shifted

Worst first, showing shifts of 0.01 and up. Each percentage is that shift's exact share of the score.

  • 0.556
    95% of CLSshifted at 2.110 s
    <div id="bodyContent" class="content">
    body > div#mw-mf-viewport > div#mw-mf-page-center > main#content > div#bodyContent
    <div class="pre-content heading-holder">
    body > div#mw-mf-viewport > div#mw-mf-page-center > main#content > div:eq(1)
    <ul id="p-views" class="page-actions-menu__list minerva-icon-only-menu">
    body > div#mw-mf-viewport > div#mw-mf-page-center > main#content > div:eq(1) > nav > ul#p-views
  • 0.026
    5% of CLSshifted at 2.946 s
    <li id="page-actions-watch" class="page-actions-menu__list-item">
    body > div#mw-mf-viewport > div#mw-mf-page-center > main#content > div:eq(1) > nav > ul#p-views > li#page-actions-watch
Layout shift

Elements that shifted by more than 0.01 are highlighted in the screenshot. If an element shifted outside the viewport, it won't appear here. Check the video or filmstrip to see the shift.

Browser Metrics

Navigation Timing
Extra timings
User Timing marks
mwStartup968 ms

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 ms3720859672

Custom metrics collected through JavaScript

There are no custom configured scripts.

Extra metrics collected using scripting

There are no custom extra metrics from scripting.

Chrome internal metrics (CDP)33
Audio handlers0
Audio worklet processors0
Documents41
Frames24
JS event listeners100
Layout objects1252
Media key sessions0
Media keys0
Nodes2173
Resources30
Context lifecycle state observers61
V8 per context datas3
Worker global scopes0
Uacss resources0
Rtc peer connections0
Resource fetchers41
Ad subframes0
Detached script states2
Array buffer contents2
Layout count14
Recalc style count18
Layout duration338
Recalc style duration331
Dev tools command duration981
Script duration1452
V8 compile duration23
Task duration3919
Task other duration795
Thread time10
Process time13
JS heap used size12550832
JS heap total size15654912
First meaningful paint1465
Visual Elements3
LargestImagemediawikiwiki-wordmark.svg
Display time833 ms
Position (x, y)53, 18
Size (w × h)120 × 18
HTML snippet
<img src="/static/images/mobile/copyright/mediawikiwiki-wordmark.svg" alt="MediaWiki" width="120" height="18" style="width: 7.5em; height: 1.125em;">
Heading
Display time2.167 s
Position (x, y)16, 497
Size (w × h)328 × 37
HTML snippet
<h1 id="firstHeading" class="firstHeading mw-first-heading"></h1>
LargestContentfulPaint
Position (x, y)16, 630
Size (w × h)328 × 1154
HTML snippet
<ul class="mw-pt-languages-list"></ul>

PageXray

How the page is built.

HTTP versionHTTP/2.0
Total requests25
Total domains2
Transfer size637.8 KB
Content size2.6 MB
Missing compression0
Cookies60 third-party

Main document

status 200 · 0 redirects

https://www.mediawiki.org/wiki/Download

HeaderValue
accept-ch
accept-rangesbytes
age11829
cache-controlprivate, s-maxage=0, max-age=0, must-revalidate, no-transform
content-encodinggzip
content-languageen
content-length18109
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content-typetext/html; charset=UTF-8
dateMon, 24 Aug 2026 20:04:29 GMT
last-modifiedFri, 21 Aug 2026 13:14:45 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';
serverATS/9.2.15
server-timingcache;desc="hit-front", host;desc="cp3070",co_id;desc="3720859672"
strict-transport-securitymax-age=106384710; includeSubDomains; preload
varyAccept-Encoding,X-Subdomain,Cookie,Authorization,User-Agent
x-analytics
x-cachecp3070 hit, cp3070 hit/7
x-cache-statushit-front
x-client-ip138.201.135.103
x-content-type-optionsnosniff
x-request-id415ea33c-d8d4-4bc5-8c0b-3da0e6278d0b

Response codes

200
2496.0%
302
14.0%

Requests and sizes per content type

7 types

Transfer size637.8 KB

  • javascript85.0%
  • css6.1%
  • html3.7%
  • svg2.5%
  • favicon1.3%
  • image1.2%
  • json0.28%

Content size2.6 MB

  • javascript84.5%
  • css11.6%
  • html2.8%
  • favicon0.57%
  • svg0.27%
  • image0.26%
  • json0.01%

Requests24

  • svg54.2%
  • javascript20.8%
  • css8.3%
  • html4.2%
  • image4.2%
  • favicon4.2%
  • json4.2%
ContentHeader SizeTransfer SizeContent SizeRequests
html0 b23.7 KB73.3 KB1
css0 b38.6 KB308.4 KB2
javascript0 b541.9 KB2.2 MB5
image0 b7.6 KB6.8 KB1
favicon0 b8.3 KB15.0 KB1
svg0 b15.9 KB7.1 KB13
json0 b1.8 KB288 B1
Total0 b637.8 KB2.6 MB24

Data per domain

2 domains
DomainTotal download timeTransfer SizeContent SizeRequests
www.mediawiki.org4.326 s636.3 KB2.6 MB24
auth.wikimedia.org186 ms1.5 KB254 B1

Expires & last-modified statistics

typeminmedianmax
Expires0 seconds4 weeks1 year
Last modified3 days7 weeks7 weeks

Console log

3 messages

The page logs the following messages to the console.

LevelMessage
WARNINGhttps://www.mediawiki.org/wiki/Download 571:52 "This page is using the deprecated ResourceLoader module \"mediawiki.ui.button\".\n[1.41] Please use Codex. See migration guidelines: https://www.mediawiki.org/wiki/Codex/Migrating_from_MediaWiki_UI"
WARNINGhttps://www.mediawiki.org/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=minerva 11:76 "This page is using the deprecated ResourceLoader module \"moment\".\n[1.44] Use mediawiki.DateFormatter or native Intl function instead. See https://phabricator.wikimedia.org/T146798"
INFOhttps://www.mediawiki.org/w/load.php?lang=en&modules=ext.centralNotice.choiceData%2Cdisplay%2CgeoIP%2CimpressionDiet%2CkvStore%2CstartUp%7Cext.centralauth.centralautologin%7Cext.checkUser.clientHints%7Cext.discussionTools.init%2Cminervaicons%7Cext.dismissableSiteNotice%2CeventLogging%2CnavigationTiming%2CtestKitchen%2CwikimediaEvents%7Cext.echo.centralauth%7Cext.eventLogging.metricsPlatform%7Cext.pygments.view%7Cext.translate.languages%7Cext.translate.pagetranslation.uls%7Cext.uls.common%2Ci18n%2Cinterface%2Clanguagenames%2Cmediawiki%2Cmessages%2Cpreferences%2Cwebfonts%7Cext.uls.rewrite.entrypoints%7Cext.urlShortener.toolbar%7Cext.wikimediaEvents.testKitchen%7Cjquery%2Cmoment%2Coojs%2Coojs-ui-core%2Coojs-ui-windows%2Crangefix%2Csite%7Cjquery.client%2Ci18n%2CtextSelection%2Culs%7Cjquery.uls.data%2Cgrid%7Cmediawiki.DateFormatter%2CString%2CTitle%2Capi%2Cbase%2Ccldr%2Ccookie%2Cexperiments%2CjqueryMsg%2Clanguage%2Crouter%2Cstorage%2Ctemplate%2Cuser%2Cutil%2CvisibleTimeout%7Cmediawiki.libs.pluralruleparser%7Cmediawiki.page.ready%7Cmediawiki.page.watch.ajax%7Cmediawiki.template.mustache%7Cmobile.codex.styles%7Cmobile.init%2Cstartup%7Coojs-ui-windows.icons%7Cskins.minerva.scripts%7Cwikibase.databox.fromWikidata&skin=minerva&version=1ycio 1510:13906 "Learn more about how we build our mobile site @ https://www.mediawiki.org/wiki/Special:MyLanguage/Extension:MobileFrontend"

Requests loaded after onLoad event

5 requests

Includes requests done after load event end.

ContentTransfer SizeRequests
html0 b0
css0 b0
javascript139.5 KB2
image7.6 KB1
font0 b0
favicon8.3 KB1
Total155.3 KB5

Requests loaded after onContentLoad

5 requests

Includes requests done after DOM content loaded.

ContentTransfer SizeRequests
html0 b0
css0 b0
javascript139.5 KB2
image7.6 KB1
font0 b0
favicon8.3 KB1
Total155.3 KB5

CPU

load.php[startup] is responsible for 87% of blocking time
895 ms of 1032 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.

TBT882 ms
Max potential input delay357 ms
Total long tasks10
Total time1.440 s
Last task at3.823 s
Before first paint108 ms1 task
Before FCP108 ms1 task
Before LCP108 ms1 task
After load1.332 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 frames11showing the 10 with the most blocking time
Blocking time1.451 sacross all long frames — what hurts INP and TBT
Forced style & layout59.3 msscripts reading layout mid-frame
Blocking before LCP410.3 msdelaying the largest paint — fix these first
Blocking after load696.6 msafter 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]61.135 s894.9 ms55.8 mstimer or animation callback
load.php[scripts:ext.centralNotice.choiceData]4212.8 ms135.8 ms3.5 mstimer or animation callback
Download18.2 ms1.2 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 · 452.2 msat 2.349 s · after load
blocking 346.5 ms
  • Scripts & other work107.7 ms
  • Animation callbacks341.2 ms
  • Style & layout3.3 ms
  • Render0 ms
6 scripts ran during this frame · forced style & layout 59.3 ms
Ran for
52 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 626181 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
6.9 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 626181 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
5.3 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 626181 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
15.5 ms
Forced style and layout
3.5 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 626181 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
12.5 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
339.6 ms
Forced style and layout
55.8 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 #2 · 428.5 msat 1.683 s · before load
blocking 343.7 ms
  • Scripts & other work344.8 ms
  • Animation callbacks56.4 ms
  • Style & layout27.3 ms
  • Render0 ms
2 scripts ran during this frame
Ran for
310.1 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
56.4 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 #3 · 400.3 msat 1.008 s · before LCP
blocking 341.3 ms
  • Scripts & other work20.1 ms
  • Animation callbacks0 ms
  • Style & layout380.2 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 #4 · 179.5 msat 3.823 s · after load
blocking 129.6 ms
  • Scripts & other work179.5 ms
  • Animation callbacks0 ms
  • Style & layout0 ms
  • Render0 ms
1 script ran during this frame
Ran for
179.5 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 #5 · 123.6 msat 3.026 s · after load
blocking 73.5 ms
  • Scripts & other work51.4 ms
  • Animation callbacks49.2 ms
  • Style & layout23 ms
  • Render0 ms
2 scripts ran during this frame
Ran for
49.9 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
49.2 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)
Long animation frame #6 · 152.1 msat 2.180 s · after load
blocking 72.7 ms
  • Scripts & other work75.1 ms
  • Animation callbacks58.9 ms
  • Style & layout18.1 ms
  • Render0 ms
5 scripts ran during this frame
Ran for
45.4 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
5.1 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 626181 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
8.3 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 626181 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
6.1 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 626181 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
55.8 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 #7 · 132.7 msat 2.814 s · after load
blocking 67.2 ms
  • Scripts & other work110.4 ms
  • Animation callbacks22.3 ms
  • Style & layout0 ms
  • Render0 ms
1 script ran during this frame
Ran for
95 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 626181 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Long animation frame #8 · 324.2 msat 470 ms · before LCP
blocking 47.3 ms
  • Scripts & other work322.4 ms
  • Animation callbacks1.8 ms
  • Style & layout0 ms
  • Render0 ms
1 script ran during this frame
Ran for
8.2 ms
Queued before running
1.9 ms
How it started
script tag
Long animation frame #9 · 125.8 msat 1.453 s · before LCP
blocking 21.7 ms
  • Scripts & other work71.4 ms
  • Animation callbacks52.3 ms
  • Style & layout2.1 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 #10 · 77.3 msat 3.153 s · after load
blocking 7.1 ms
  • Scripts & other work57.2 ms
  • Animation callbacks8.6 ms
  • Style & layout11.5 ms
  • Render0 ms
2 scripts ran during this frame
Ran for
18.6 ms
Started by
TimerHandler:setTimeout
How it started
timer or animation callback
Position in source
character 626181 into the file (locate it via DevTools → Performance → the Long Animation Frames track)
Ran for
36.9 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)

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]
895 ms · 10 frames · worst 291 ms
load.php[scripts:ext.centralNotice.choiceData]
136 ms · 9 frames · worst 58 ms
https://www.mediawiki.org/wiki/Download
1 ms · 1 frame · worst 1 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.

TBT1.438 s
Blocking tasks14
TBT before LCP439.4 ms3 tasks

What kind of work blocked

mostly running javascript · 1.439 s total
Running JavaScript810.5 ms56.3%
Style & layout469.1 ms32.6%
Paint & composite81.7 ms5.7%
Other browser work43.5 ms3.0%
Parsing HTML & CSS20.7 ms1.4%
Garbage collection12.7 ms0.9%
Parsing & compiling JavaScript0.4 ms0.0%
Running JavaScript (56%): the scripts responsible are listed right below. See Slowest JS functions · Timers
Style & layout (33%): usually a large DOM, expensive CSS selectors or JavaScript forcing synchronous layout. See Forced reflows · Forced layout per script · Style invalidations (Rendering tab)

Top scripts blocking the main thread

3 of 3 scripts
load.php[startup]
839 ms · 7 tasks
Browser's own work (no script responsible)
552 ms · 5 tasks

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

3.201 s total
Running JavaScript1.607 s50.2%
Style & layout673 ms21.0%
Other browser work (scheduling)544 ms17.0%
Parsing HTML & CSS176 ms5.5%
Paint & composite155 ms4.8%
Parsing & compiling JavaScript30 ms0.9%
Garbage collection16 ms0.5%
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 537 ms of it is this per-task bookkeeping (RunTask self time in the trace).

CPU time per script

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
flushWrites
runs: load.php[startup] (25.8 ms)
load.php[startup]150.2 ms176.0 ms
runScript
runs: load.php[scripts:ext.centralNotice.choiceData] (420.5 ms), load.php[scripts:@wikimedia/codex] (45.6 ms)
load.php[startup]100.8 ms823.1 ms
insertBeforeBrowser internal (not your code)72.1 ms72.1 ms
setAttributeBrowser internal (not your code)53.7 ms53.7 ms
(anonymous)load.php[scripts:ext.centralNotice.choiceData]50.2 ms50.2 ms
require
runs: load.php[scripts:ext.centralNotice.choiceData] (168.5 ms), load.php[scripts:@wikimedia/codex] (45.6 ms)
load.php[startup]37.3 ms164.4 ms
resources/lib/vue/vue.js
runs: load.php[scripts:@wikimedia/codex] (14.1 ms)
load.php[scripts:@wikimedia/codex]31.6 ms45.6 ms
impl
runs: load.php[scripts:ext.centralNotice.choiceData] (4.7 ms), load.php[scripts:@wikimedia/codex] (1.3 ms)
load.php[startup]30.6 ms37.6 ms
setTimeoutBrowser internal (not your code)30.6 ms30.6 ms
t
runs: load.php[scripts:ext.centralNotice.choiceData] (229.2 ms)
load.php[scripts:ext.centralNotice.choiceData]23.9 ms221.3 ms
doPropagation
runs: load.php[startup] (418.5 ms), load.php[scripts:ext.centralNotice.choiceData] (1.6 ms)
load.php[startup]22.6 ms442.6 ms
set
runs: load.php[startup] (1.1 ms)
load.php[startup]22.4 ms24.3 ms
(anonymous)
runs: appendChild (1.6 ms)
load.php[scripts:ext.centralNotice.choiceData]21.9 ms23.5 ms
requestIdleCallbackBrowser internal (not your code)16.9 ms16.9 ms
buildFragment
runs: load.php[scripts:ext.centralNotice.choiceData] (1.6 ms), appendChild (1.2 ms)
load.php[scripts:ext.centralNotice.choiceData]15.6 ms19.4 ms

Timers

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 set53
Times fired51
Fire time267.6 ms
Zero-delay timers48
Repeating timers0
Zero-delay slicing: load.php[scripts:ext.centralNotice.choiceData] split work into 46 back-to-back tasks costing 255 ms. Consider batching the work or moving it to requestIdleCallback or a worker.

Timer cost by script

2 scripts
load.php[startup]
147 ms · set 1 time · fired 16 times
load.php[scripts:ext.centralNotice.choiceData]
121 ms · set 52 times · fired 35 times

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

4 reflows ≥ 2 ms across 2 scripts
load.php[startup]
56 ms · 3 reflows · worst 45 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
load.php[startup]
56 ms · across 1 frame

First vs third party CPU time

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

First party1.553 s
Third party0 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.