We need to update/extend the documentation on https://www.mediawiki.org/wiki/Extension:RevisionSlider:
- add step about extending/collapsing RS to the usage instructions
- add documentation about new opt-out setting
- add a section about technical background of the tool
- what happens when RS is collapsed (no API calls, etc..)
- what happens when RS gets expanded
- Additionally the German translation needs to be updated and revised: https://www.mediawiki.org/wiki/Extension:RevisionSlider/de