You can find some reports here by using Translation software(If this report hasn't been deleted yet)。
BiliBili once made a statement on Weibo， but delete in a few minutes.
https://www.heibai.org/post/1214.html
You could link to the hearsay, assuming it was online.
FWIW, the report you link in your other comment has a screenshot of a conversation where someone claims that the code was leaked by an intern from Nankai University who didn't know how to use git. [1] That they're identified by their university makes me suspect that it's a rumor (edit: making fun of the university), though.
