Page summary

The page has 3 images (out of 3) 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

• https://query.wikidata.org/querybuilder/img/close.svg
• https://query.wikidata.org/querybuilder/img/search.svg
• https://query.wikidata.org/querybuilder/img/clear.svg

First contentful paint can be improved (1.900 s). It is in the Google Web Vitals needs improvement range, slower than 1.8 seconds.

The First Contentful Paint (FCP) metric measures the time from when the page starts loading to when any part of the page content is rendered on the screen. For this metric, "content" refers to text, images (including background images), <svg> elements, or non-white <canvas> elements.

The page has 1 CPU long task with the total of 124 ms. The total blocking time is 0 ms and 1 long task before first contentful paint with total time of 124 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

The page has 8 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

• https://query.wikidata.org/querybuilder/assets/index.97f88779.js
• https://query.wikidata.org/querybuilder/assets/index.58783912.css
• https://query.wikidata.org/querybuilder/i18n/en.json
• https://query.wikidata.org/favicon.ico
• https://query.wikidata.org/querybuilder/img/QB_Logo.svg
• https://query.wikidata.org/querybuilder/img/close.svg
• https://query.wikidata.org/querybuilder/img/search.svg
• https://query.wikidata.org/querybuilder/img/clear.svg

The page is missing a meta description.

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

There are 10 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

• https://query.wikidata.org/querybuilder/
• https://query.wikidata.org/querybuilder/assets/index.97f88779.js
• https://query.wikidata.org/querybuilder/assets/index.58783912.css
• https://query.wikidata.org/querybuilder/i18n/en.json
• https://query.wikidata.org/favicon.ico
• https://www.wikidata.org/beacon/statsv?Wikidata.query-builder.main-page-loaded=1c
• https://query.wikidata.org/querybuilder/img/QB_Logo.svg
• https://query.wikidata.org/querybuilder/img/close.svg
• https://query.wikidata.org/querybuilder/img/search.svg
• https://query.wikidata.org/querybuilder/img/clear.svg

No <meta name="referrer"> tag was found on the page. Set a Referrer-Policy response header (preferred) or add a meta tag, for example <meta name="referrer" content="strict-origin-when-cross-origin">.

Without an explicit referrer policy the browser falls back to the user-agent default and may leak the full URL of the previous page (including query strings) to every cross-origin request. Set a Referrer-Policy response header (preferred) or a <meta name="referrer"> tag in the document. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referrer-Policy

Set a Content-Security-Policy header to mitigate cross-site scripting attacks. You can start with a Content-Security-Policy-Report-Only header, which only reports violations rather than blocking them.

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

Offenders

• https://query.wikidata.org/querybuilder/

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

• https://query.wikidata.org/querybuilder/

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

• https://query.wikidata.org/querybuilder/

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

• https://query.wikidata.org/querybuilder/

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

• https://query.wikidata.org/querybuilder/

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

• https://query.wikidata.org/querybuilder/

Set X-Content-Type-Options: nosniff on the document response to prevent MIME-sniffing.

X-Content-Type-Options: nosniff prevents browsers from interpreting files as a different MIME type than what is declared in the Content-Type header. This blocks a class of cross-site scripting and content-type confusion attacks and should be set on every response. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options

Offenders

• https://query.wikidata.org/querybuilder/