This is in the Steamworks Distribution Program Agreement, section 2.1. Specifically:
Quote
What does this mean? Well, basically Mechwarrior 5 either releases on Steam the same time it releases on EGS, or it will never be able to release on Steam.
It's likely that PGI already signed an agreement with Epic and is no longer able to back out now. For as long as this clause is in place, there is no chance that MW5 will ever make it to Steam.
To clarify, this was updated in 2017 but hasn't been enforced. The concern now is that they can let a game like Red Dead Revolver 2 launch on Steam to cash in on big titles, but block games like Mechwarrior 5 who took Epic's shilling.
Will they? Well, they're in a bit of a cold war with Epic, so it's very possible.
*updated to add entire delivery section to quote.
*Second update for clarity
Edited by S3dition, 12 September 2019 - 06:17 PM.