A pure measurement over a rendered document (fixtures and live): text and icon contrast over the
painted backdrop, X colour leakage, truncated bar/nav/button labels, bar geometry and hit tests, X line
icons under a pack, empty and nested frames, popover bounds, target sizes. Grew out of theme-qa/probe.js.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
