So UE4 is now free...

Since the unreal editor requires you to log in with an account - I don’t see how you can really ‘bundle’ it in. But can’t you just as easily point players to the official website to get it themselves, now that it’s free?

Edit:

Actually I didn’t think about modded versions of the editor and the like - so yea you’d want to be able to bundle it. But Tim Sweeney answered it in another pose: