Comment by KaiserPro

If you distribute a binary to someone, with gpl2, you should also, if asked provide the source code used to _build_ that binary. Other licenses will differ. MIT for example lets you do pretty much anything, so long as you keep the MIT license and attribution public.

But when people are talking about open source, they generally mean "oh I can see the source code and build it my self." rather than freeware which is "I can run the binary and not have to pay"