Per Nikerabbit's comment at https://www.mediawiki.org/wiki/Special:Code/MediaWiki/81210#c13635
It's unclear if it's feasible and if it can be done without cluttering the special pages too much or reducing flexibility (compare T13612: Maximum to "Days to show in watchlist" in preferences should equal $wgRCMaxAge comment 13).
Could be useful for T22151: Preferences for anonymous users (allowing only a subset of preferences)?
See Also:
T54807: Identify and remove legacy preferences from MediaWiki core (tracking)