This is a tracking task for user preferences in MediaWiki core to be removed.
See Also:
Extensions are getting heavy on preferences, too, so generalising the summary; if you prefer to split those to a sister tracking bug for some reason, feel free.
@Krinkle: it looks like we briefly discussed this one in E157 just before moving it to the backlog. This looks like a sea of links that would be really easy to get lost in. Is this something that you'd like to handle as an TechCom-RFC? Do you think we should queue this up for an IRC meeting?
T64559: Redesign Special:Preferences (tracking) seems a worthwhile RFC to me.
I've split T42346 from this one to continue as separate exploration (not an RFC right now).
This task (T54807) about identifying and removing so-called "legacy" preferences is marked as RFC right now. I agree that it doesn't seem like something we'd handle as RFC. Rather this is more a tracking task that tracks individual tasks that discuss the removal of individual preferences, each of which may have its own story, I don't see a general RFC that would resolve them all.
The RFC left here could be to discuss how we want to identify legacy preferences. To establish consensus about a policy detailing what criteria to apply and how to decide when to remove a preference. So far this doesn't seem very controversial though. We've successfully removed such legacy preferences through regular discussion and code review without the overhead of an RFC to establish a formal policy.
This wasn't originally marked as RFC (I did that last month as part of the split, I've undone that edit and restored this as a tracking trask).