Pages runs Jekyll by default. Jekyll ignores paths beginning with an underscore and carries default `vendor/` exclusions, neither of which suits a hand-built page — and the failure mode is an asset that silently does not publish, which for this page means the playground's compiler 404s and the Run button dies exactly the way the old CDN-based one did. `.nojekyll` opts out, so what is in docs/ is what gets served. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01SAcqrz3FcadkYr3xG32CjK