I guess it is ported version:
https://github.com/LemonHaze420/DCPopulous/blob/4cd8b7562191...
It's license dialog has a link to http://www.portable-games.com/populous
https://github.com/LemonHaze420/DCPopulous/blob/4cd8b7562191...
It's license dialog has a link to http://www.portable-games.com/populous
https://github.com/LemonHaze420/DCSpeedBall2/blob/e6d9ce3c11...
I don't remember Speedball 2 having a DreamCast port, so these repositories seem somewhat strange. They are also strange for missing license files and various other asset files.