As I can't find this in the documentation (but now here on Issues on a screenshot) I reported here: https://phabricator.wikimedia.org/T232142 (closed because of this).

Edit: The relevant code seems here:

It seems very false to take the creator of the file (but I don't get the code on

As a maintainer of the desktop version, I can say there is an Api request needed to get the list of uploaders (here it seems there is only taken a single user/string, but I don't understand Java really).