Soo… Some characters are not valid in URLs (or not used for other reasons) and must be replaced. In this case, the + is percent-encoded to %2B, which renders Loss_(Ctrl+Alt+Del) as Loss_(Ctrl%2BAlt%2BDel), which is a perfectly fine URL (cut off the front for clarity).

Hower, something on the client (OS, browser) then seems to look at that URL and think that the percent sign cannot be there and encodes that again to yield Loss_(Ctrl%252BAlt%252BDel).

When Wikipedia looks at this and tries to figure out the page to load, it de-encodes that string back to Loss_(Ctrl%2BAlt%2BDel) and seems to stub its toe on the %2B, if @SpaceNoodle@lemmy.world is to be believed.

https://en.wikipedia.org/wiki/Percent-encoding