Change #1239149 had a related patch set uploaded (by Ammarpad; author: Jdlrobson):

[mediawiki/extensions/SandboxLink@master] "new" class should apply to link NOT list item

https://gerrit.wikimedia.org/r/1239149

Tested the patch on several skins:
(demo wikis: before: https://patchdemo.wmcloud.org/wikis/c93b0ed9a0, after: https://patchdemo.wmcloud.org/wikis/844a4c67e5)

	Vector 2022	Vector 2010	Minerva	Timeless	Monobook
Before
After

So it appears that it fixes the bug on Vector 2022, Vector 2010, and Monobook; and has no effect on Timeless (which was not affected by the bug) and on Minerva (still bugged).

I don't know why the link color stopped appearing correctly in so many skins recently. It definitely worked in 2014 when I wrote this code (https://gerrit.wikimedia.org/r/c/mediawiki/extensions/SandboxLink/+/157296/5/SandboxLinkHooks.php#66). The link-class option may not have existed at the time, or maybe it wasn't widely supported by skins, but it seems more correct to use that today.

One last note, I noticed something weird on Minerva: when hovering the link with the mouse cursor, it displays a red underline before the patch, but not after. This seems like it intended to support the old code (with class) – although it didn't work correctly – but does not support the new code (with link-class). It doesn't really work anyway, so I don't mind this.

	Minerva
Before
After

Change #1239149 merged by jenkins-bot:

[mediawiki/extensions/SandboxLink@master] "new" class should apply to link NOT list item

https://gerrit.wikimedia.org/r/1239149