I have merged the Gerrit change (
https://gerrit.wikimedia.org/r/#/c/124475/),
restoring the body font to "sans-serif". The heading font is unchanged for now.
I've read the entire wikitech-l thread (89 emails as of writing) and
pondered this carefully. My summary of the situation is:
* This font stack, according to WMF Design, only provides real
improvements for Macs (~6% of Wikimedia sites visitors per
<http://stats.wikimedia.org/wikimedia/squids/SquidReportOperatingSystems.htm>)
and should be (nearly) identical to defaults for other systems.
However, it causes major rendering issues for an unspecified number
of Windows and Linux users (especially with, respectively, Helvetica
and Nimbus Sans L; see both open and closed dependencies of bug
63549).
* This font stack also apparently causes issues with non-Latin-script
languages (not very well-specified ones, though; more bug reports
like bug 63817 would be welcome); it's serious enough for at least
one affected Wikimedia wiki (the Japanese Wikipedia) to have already
reset the stack to "sans-serif". This might affect the serif heading
fonts more than the sans-serif body fonts (again, more precise
reports needed).
* The wikitech-l discussion, as well as various on-wiki discussions
(e.g. on WP:VPT on the English Wikipedia) have been overwhelmingly
in favor of restoring the plain "sans-serif" font definition.
* Orthogonally to these issues, all other aspects of the typography
refresh have been generally considered successful and minor problems
with them have been quickly fixed.
Based on the points above and my own common sense I think this should
be merged, and a similar follow-up for serif heading fonts might also
be necessary (but that's obviously a lower-severity problem, there
isn't that much text in headings). Steven, I'm sorry, but I'm
overriding your -2.
(I'm posting this on the Gerrit change
<https://gerrit.wikimedia.org/r/#/c/124475/>, on the tracking bug
<https://bugzilla.wikimedia.org/show_bug.cgi?id=63549> and in the
wikitech-l thread. Please reply on wikitech-l.)
--
Matma Rex