A quick wiki visit says the term open source existed before the OSI. But that's not really important.
I just wanted to point out that UE4 does a better job than many other engine (and software!) vendors, since they give you a peek at the source and I think this should be praised, rather than scolded for not being totally free.
I just wanted to point out that UE4 does a better job than many other engine (and software!) vendors, since they give you a peek at the source and I think this should be praised, rather than scolded for not being totally free.