@SammyGalen @endali Having access to the souce code is not the same as open source. You need Unreal's permission to use or even see the source code, and this among other things makes it incompatible with the open source model.

When I modify a piece of open source software I can publish those changes and the whole community benefits from it. On the other side if I use Unreal Engine and make changes that could benefit others I would keep them for myself. Because it would benefit Epic the most, and I don't want to help making Epic more rich and powerful while I don't receive a dime from them.