Even if they were released publicly, I doubt they’d be worth using. Internal non-public engines like that tend to be a dog to actually use, because the users aren’t paying and don’t really have to be supported in the same fashion. Ease of use definitely suffers.
I might check them out but I probably wouldn’t bother trying to actually complete a game using them. For all the other tradeoffs you get from an engine like UE4 or Unity, they were built to be used by smaller developers and teams, which means a focus on usability that internal non-public engines just can’t match.