Google Lighthouse V8 – Improved CLS metrics

Full Changelog

We expect this release to ship in the DevTools of Chrome 93, and is already in PageSpeed Insights!

Notable changes

• The Performance Category had a number of scoring changes to align with other performance tools and to better reflect the state of the web.

  • The Performance Score has been reweighted (#12577)
  • The TBT and FCP score curves have been updated (#12576, #12556)
  • CLS has been updated to its new, windowed
    definition (#12554)

  See the v8.0 Performance FAQ for more detail.

  

• The report includes a new metric filter. Pick a metric to focus on the opportunities and diagnostics most relevant to improving just that metric:

  

• The Lighthouse Treemap is now available across all the major Lighthouse clients. If your site exposes source maps to Lighthouse, look for the "View Treemap" button to see a breakdown of your shipped JavaScript, filterable by size and coverage on load.

🆕 New audits

• The new audit csp-xss has been added to Best Practices to evaluate Content Security Policies and suggest ways of making them more secure. This can be a challenging audit to pass depending on hosting environment and page content, so for now it is unscored (#12514, #12551)

🤖💥 Breaking changes for programmatic users

• Legacy metrics estimated-input-latency and first-cpu-idle have been deprecated, unweighted, and hidden since Lighthouse 6. They have now been removed (#12553)
• Starting with Node 13, Node is built with full-icu by default, so the very large intl polyfill has been removed from Lighthouse's dependencies. See the readme FAQ if you're stuck with small-icu but need localization support (#12426)
• Long-time audit uses-webp-images has a new ID, modern-image-formats. WebP is now rather mainstream, and this frees the audit to start including details on other cutting-edge image formats in the future (#12535)
• The image-elements artifact has been restructured for clarity (#12568)

🧱 Core

• navigate: only observe longtasks in PerfObserver (#12545)
• script-treemap-data: do not create nodes with blank names (#12569)

⛏️👷 Fraggle Rock

Support for auditing user flows (#11313)

• add settings to gather context (#12574)
• fix usage of distributed conditional type (#12565)
• support inspector-issues gatherer (#12530)
• support tags-blocking-first-paint gatherer (#12527)
• support response-compression gatherer (#12508)
• align navigation-runner with legacy gather-runner (#12478)

📔 Report

• improve accessibility of metric filter (#12552)
• treemap: add placeholder, gist, and file upload features (#12511)
• treemap: support passing gzipped data in url (#12509, #12519)
• viewer: fix gist icon (#12505)

👥 Clients

• fix main session OOPIF checks for devtools (#12533)
• render treemap button in all clients (#12516, #12570, #12590)
• backport proto formatting fixes (#12566)

🌍 i18n

📋 Tests

• run unit tests on all active node versions in CI (#12513)
• sync devtools webtests (#12578)
• treemap: reduce debug.json (#12555)

🕸️ Deps

• update lighthouse-plugin-publisher-ads to 1.4.1 (#12592)
• update axe-core to 4.2.1 (#12575)
• update puppeteer to 9.1.1 (#12284)
• update chrome-launcher to 0.14.0 (#12507)

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