HedgeDoc lacks a commenting feature. This is the most requested collaboration gap (issues #657, #2879, #5450) and a blocker for teams evaluating HedgeDoc as a Google Docs alternative. The community and maintainers have debated inline vs. out-of-band approaches for years without converging on a design.
Inline comments using CriticMarkup syntax, stored directly in the markdown document. A CodeMirror 6 extension hides the raw syntax and provides a clean UI. No backend changes required.