Board Thread:Technical Updates/@comment-24006128-20200423160701/@comment-1038387-20200427130540

That original editor wasn't even an editor - it was just raw source. The source editor always existed. However, for UCP wikis, the choice at the moment is only Visual Editor of Source Editor, which you can pick in your Preferences. In the first week, it was possible to disable the editors completely, but this has changed (and retroactively to boot). However, the UCP's Source Source was different from the old source with the right module rail etc.; it was closer to vanilla source like Wikipedia has.

If you want the Source Source back, air your feedback with this. I hope it's just temporary because they want to port the current look over, but haven't heard anything about it.