- Preview UI Mode with built‑in watch mode and ui flag for exploring, running, and debugging tests.
- New APIs: updateMode/updateContent options for page.routeFromHAR and browserContext.routeFromHAR, TestInfo.testId property, Tracing.startChunk() option, and locator chaining support.
- Breaking change: component tests now require React 18; use @playwright/experimental‑ct‑react17 for React 16/17.

