To work on the diff feature (e.g. T346369: Diff-type selection resets back to "wikitext" when using RevisionSlider) we want to have the same setup as on live wiki in our docker dev. https://gitlab.com/wmde/technical-wishes/docker-dev
https://www.mediawiki.org/wiki/Help:Diff#Inline_diffs
https://www.mediawiki.org/wiki/Wikidiff2
Code to review: https://gitlab.com/wmde/technical-wishes/docker-dev/-/merge_requests/121