Performance Chat Summary: 16 December 2025

The full chat log is available beginning here on Slack.

WordPress Performance Trac tickets

• @westonruter shared that he is still working through fixes for a CSS issue introduced in WordPress 6.9 related to loading separate block styles on demand in PR #10601.

Performance Lab Plugin (and other performance plugins)

• @westonruter noted that several PRs needs to be reviewed.
• @b1ink0 asked for feedback regarding the planned sunsetting of the Web Worker Offloading plugin issue #2284.

Open Floor

• @westonruter shared that Safari now supports measuring the LCP metric, which he said will meaningfully improve URL Metric collection for Optimization Detective
  • @spacedmonkey wondered whether the team could begin running the performance core e2e tests against Safari now that the browser includes this capability.
• @westonruter added that he is interested in exploring Compression Dictionaries after learning they can be implemented in PHP with relatively little effort referenced article.
• @b1ink0 shared information regarding the final 2025 meeting to discuss the 2026 roadmap, scheduled for December 23, 2025.

Our next chat will be held on Tuesday, December 30, 2025 at 16:00 UTC in the #core-performance channel in Slack.

#core-performance, #hosting, #performance, #performance-chat, #summary