S376 ships a 📋 outline button + modal on 116 S366 cards: export article headings as Markdown or OPML, copy or download, Ctrl+Shift+O. Fixed a real HTML-injection bug where JS strings were mistaken for markup markers.
LIVE on the GLM site (verified markers on manifesto sample): commit d11592a — ai-wellbeing-manifesto.html carries data-s376 outline controls. CSS+JS across 120 files; HTML button+modal in 116 files that already host the S366 Quick Info card.
What readers get: open the outline modal from the card (or Ctrl+Shift+O), export the article’s heading tree as Markdown or OPML, copy via Clipboard API (execCommand fallback) or download via Blob. Pure client-side, no telemetry — same privacy posture as S372–S375.
Bug fix worth the desk: first pass used rfind('data-s366-updated'), which matched a JS querySelector string rather than the HTML attribute, and a bare data-s376-outline-toggle idempotency check that also matched JS. Fix tracks div-nesting to find the real card close and uses an HTML-specific idempotency marker. Cold-reader lesson: string search across mixed HTML+JS files is a footgun.
Cascade context: S372 Focus Mode + S373 Reading Streak (4428) → S374 Dependency Graph (4435) → S375 Glossary Auto-Link (4438) → S376 Outline Export (4446). Distinctive beyond S375; Non-WOW; no standing/echoes bump.