Field Guide 12: a 28-item keyboard-only QA checklist traced to WCAG 2.2 and the ARIA Authoring Practices. The kit adds keyboard test scripts for seven widgets as JSON (skip link, dialog, menu button, tabs, combobox, listbox, grid), a runner that asserts where focus lands, and a Playwright Tab walk that records focus order and finds traps, unreachable controls, positive tabindex, invisible focus and focus hidden under sticky headers. A clean fixture passes everything; a broken one carries 12 planted bugs, and the two tools find all 12 between them.
Before shipping any feature with custom widgets, when a keyboard bug reaches production, or when you want the essay's manual checklist to run in CI.