Every Twitch Developer has 2FA even 3rd party developers are required to have 2FA I also think, but don't know, that this applies to Twitch Broadcaster Partners as well in order to have their tax information in the system.

Luckily iirc from a conversation with a senior Twitch engineer the Tax information backend has been migrated to Amazon. So hopefully that did not leak... Because that would be full legal name and addresses of a ton of streamers that likely have stalkers.