<objective Chrome-only testing gives false confidence: a layout that works in Chromium can break in WebKit, a clipboard call that succeeds in Chrome silently no-ops in Firefox, and a partitioned-cookie flow can pass everywhere except the one engine your users are on. This skill produces an analytics-driven browser matrix, a Playwright (or cloud-platform) config that runs it, and a committed log of known browser divergences — each verified by a test that asserts the user outcome, not the CSS. </objective Quick Route | Situation | Go to | |-----------|-------| | Need to decide which browsers to…