Could also have been one of the devs who leaked it. Lots of us keep copies of the source for stuff we work on, so they may have figured it’s been long enough that no one would care if it leaked. However, I haven’t looked at it yet, but I imagine it would be most problematic legally if it contained proprietary 3rd party code. Leaking that could land someone in hot water.
Most likely not legally. Possibly by luck, possibly through compromised systems or people.
Or the people who coded it left it on a hard drive that was auctioned off or obtained by whatever means.
Could also have been one of the devs who leaked it. Lots of us keep copies of the source for stuff we work on, so they may have figured it’s been long enough that no one would care if it leaked. However, I haven’t looked at it yet, but I imagine it would be most problematic legally if it contained proprietary 3rd party code. Leaking that could land someone in hot water.