Compare https://meta.wikimedia.org/wiki/Tech#Color_of_red_links_across_Mediawiki (where first reported) with https://en.wikipedia.org/wiki/Wikipedia:Red_link
The core definition of red links for all skins is #d33, which is part of the Wikimedia Design Style Guide color palette.
In Vector (legacy) this was overriden to #ba0000 for normal 'new' ('red') and #a55858 for visited new links (and normal Vector tabs new links).
- Vector (legacy) should show #ba0000 for normal 'new' ('red') links
- Vector (legacy) should turn color to #a55858 for visited 'new' ('red') links
- Vector (legacy) should show #a55858 on Vector Tabs new links, like empty Discussion pages, both in normal and visited state
- Vector (modern) should be unchanged and have #d33 for normal 'new' ('red') links