- Affected components: MediaWiki core, skins and extensions.
- Persist / possibly improve user experience by enabling skin interfaces using of rem units, making them fully text zoomable by users with accessibility needs and do away with pixel based text and image sizing
- Simplify design–development handover by doing away with close to incomprehensible em based sizing
See T262928: Use opinionated `rem` setting across Wikimedia Foundation deployed skins for more information on the negative effects of somewhat sticking to ems.
Note that the reality of supporting Firefox 3.0+ in MediaWiki core was not fully reflected for a while any more.
Firefox 3.5 was the first version to include crucial rendering and interaction properties like
- media queries,
- full ::before and ::after support
- opacity instead of -moz-opacity property
which have been widely used in core.
Firefox 3.6 on the other hand has introduced rem support and additionally from the more often used properties background-size or pointer-events.
I'm proposing to bump Firefox to at least v3.6+ in “Basic” in the browser support matrix. It was released Jan 21, 2010.
This would be effective in MediaWiki 1.36, to be released in 2021.
Turnillo shows that use of Firefox 1-3 is approximately 580K per week across the wikis, with no particularly high usage in any given country. While this includes version 3.6 and falls well below the 1% threshold applied to other such decisions before, we've found out in process, that Wikimedia wikiprojects are limited to TLS 1.2+ since Jan 2020, see T238038 and therefore isn't accessible at all any more for Firefox lower than 27, including Firefox 3.