User blog comment:MisterWoodhouse/Unified Community Platform: The Vision, Purpose, and Process/@comment-1333593-20200930191545/@comment-1333593-20201002063650

It seems like I'll be answering my own question... The bars on the 2010 editor are page-anchored, and very much usable in desktop mode on Android Chrome. It just does not seem to be the default setting for those that had source editing as default before the migration. It needs to be changed from "My Preferences" and saved. Without this step, switching to source mode triggers the visual editor's source mode instead (which is pretty much useless on a mobile device).