While we're moving forward to rely on a standardized set of variables to enable using general variables with an override/call of WikimediaUI Base variables for Wikimedia projects to be relied on,
- it's necessary to deprecate mediawiki.ui's variables and
- rename the remaining variables to new naming scheme resulting in equal variables like in WikimediaUI Base in a go
This task is limited to MediaWiki core. Skins and extensions are targeted in separate tasks.