When trying to apply any text formatting option ( bold, italic, strike-though ... ) the server throws an exception with
TypeError: Cannot read property 'static' of undefined\n at /home/chfi/projects/VisualEditor/dist/ve-rebaser.js:3348:36 at Array.every (<anonymous>) at VeDmTransaction.ve.dm.Transaction.translateOffset (/home/chfi/projects/VisualEditor/dist/ve-rebaser.js:3347:14) at VeDmTransaction.ve.dm.Transaction.translateRangeWithAuthor (/home/chfi/projects/VisualEditor/dist/ve-rebaser.js:3424:16) at VeDmLinearSelection.ve.dm.LinearSelection.translateByTransactionWithAuthor (/home/chfi/projects/VisualEditor/dist/ve-rebaser.js:5980:34) at VeDmLinearSelection.ve.dm.Selection.translateByChange (/home/chfi/projects/VisualEditor/dist/ve-rebaser.js:5705:25) at Object.ve.dm.Change.static.rebaseUncommittedChange (/home/chfi/projects/VisualEditor/dist/ve-rebaser.js:4106:70) at VeDmRebaseServer.applyChange (/home/chfi/projects/VisualEditor/dist/ve-rebaser.js:4845:38) at VeDmProtocolServer.ve.dm.ProtocolServer.onSubmitChange (/home/chfi/projects/VisualEditor/dist/ve-rebaser.js:5152:36) at /home/chfi/projects/VisualEditor/dist/ve-rebaser.js:5257:14 at process._tickCallback (internal/process/next_tick.js:68:7)
It's obviously due to missing dependencies not pulled in.
Note: Looked into this on a WMDE hack day and continued a bit on the Wikimedia-Hackathon-2021.