Not too long ago, the folks at OldUnreal announced in their Discord server that they got permission from Epic Games to distribute two particular links from archive.org to download Unreal Gold and Unreal Tournament.
Now they've published installers for automating the installation process, as well as installing their patches on top of Unreal/UT.
The installers are available to download on the links down below:
Considering the OldUnreal team still has access to the source code for these two games, and develop patches for them to this day, I find it, thankfully, extremely unlikely!
id Software led the way, decades ago, making Doom and then Quake engines open source. I wish more studios would donate their old software to the public domain.
Fingers crossed one day we will get Unreal source code. I wonder if it even still exists.
Old Bungie also opened up the Marathon engine and released the assets before the Microsoft takeover. You can play that game on any modern platform while Oni is lingering in abandonedware land, unplayable and unprofitable.