Around 2015, when VisualEditor configuration for enwiki and dewiki was being changed from default-off to default-on, these two features were introduced to ease the transition:
- VisualEditorTransitionDefault configuration option makes it so that when you enable and then disable the beta feature in preferences, the fact that you opted out is recorded in the 'visualeditor-autodisable' preference, so that when the default changes, your account wouldn't be affected.
- AutodisableVisualEditorPref maintenance script was used to also set the 'visualeditor-autodisable' preference for all users with edits at the time, so that they wouldn't be affected either.
There are probably some tasks around from that time somewhere, I didn't look too hard.
As far as I know this mechanism wasn't used since then. We haven't used it for any of the later VisualEditor rollouts (https://gerrit.wikimedia.org/r/plugins/gitiles/operations/mediawiki-config/+log/master/dblists/visualeditor-nondefault.dblist).
It seems unlikely that we'll use it again. Maybe it's time to remove it?