Per [[https://www.mediawiki.org/wiki/Template:Compatibility_browser]] we no longer have any browsers in "Basic" / "Grade C" support that don't handle SVGs and in particular `linear-gradient` rules.
Let's confirm we're OK to make this change, locate all the places we're still doing this, and implement?
Update 2023: We are ok. **Let's do it!**
[Note: This does not apply to user-contributed SVGs //e.g.// from Commons, which are handled differently for security reasons.]
== Acceptance criteria for done
[] Remove all fallback code: double `background-image` notations with PNGs and `transparent, transparent` hack before SVG url… [[ https://codesearch.wmcloud.org/search/?q=transparent%2C%20transparent&i=nope&files=&excludeFiles=&repos= | Codesearch ]]
[] Remove all fallback PNGs. All of above in WMF-maintained repositories
[x] Wikibase - https://gerrit.wikimedia.org/r/989135
[x] Wikibase-Lexeme - https://gerrit.wikimedia.org/r/c/mediawiki/extensions/WikibaseLexeme/+/989137
[x] ~~WikibaseDataValuesValueView~~ Only used by external lib jquery.ui.inputextender
[x] Wikidata.org - https://gerrit.wikimedia.org/r/c/mediawiki/extensions/Wikidata.org/+/989139
[x] ~~#kartographer~~ Only used by external lib leaflet
[x] #mediawiki-extensions-readinglist
[x] #mediawiki-extensions-cargo
[x] Skin #monobook
[x] Skin #Nostalgia
Note, we're leaving skin #cologneblue untouched, as it's still supporting MW 1.36
Misc:
[x] ArticleFeedbackv5
[x] Skin DarkVector – https://github.com/dolfinus/DarkVector/pull/35