Motivation
Affected components: MediaWiki core, all skins/extensions, Wikimedia Foundation product, third-parties.
Android up to 4.4.4 is currently responsible for many of the remaining -webkit- vendor prefixed properties in render critical CSS, for example on transition property. (Chrome up to 42 is the other one, but that's more neglible as it's non-existent in our access stats with Chrome 38 as somewhat significant outlier with up to 0.5% of pageviews 2021 according to analytics.wikimedia.org)
Statistics
Turnilo breakdown (login only) of OS family, major and minor versions for last 30d, showing Android 4.2 leading, 4.4 behind, 4.3 and others basically non-existing. Altogether at widely under 1%.
Possible alternative to proceed on
Focus on CSS only and remove -webkit- vendor properties and leave JS support, browserslist-config-wikimedia and infrastructure access untouched.