A completely baseless claim ... "probably" means > .5 probability, but there is no evidence to support that; it's sheer speculation.
There are more if you include special pages, like Citogenesis reported by sibling.
The other way around, folks at the Explain xkcd wiki have categorized the comics and 56 of them reference Wikipedia. [1]
[0] https://en.wikipedia.org/w/index.php?title=Special:Search&fu...
[1] https://www.explainxkcd.com/wiki/index.php/Category:Wikipedi...
Edit: I asked Opus 5.5, medium effort, and got a lame answer. Then asked it for "extra" effort, and the summary of that is:
WP->xkcd: Ballmer Peak, Geohashing, Time, a few other passing mentions
xkcd->WP: Missal of Silos, Rolle's Theorem, at least 54 other general references to WP