I already clarified that technically it's probably open source "Probably" because some projects like this don't actually include all parts of the source. FreeF

I already clarified that technically it's probably open source "Probably" because some projects like this don't actually include all parts of the source. FreeFileSync for example which claimed to be opensource, and they distributed some source, did in fact lack many parts, not just build files but actual source files (I think it can be built nowadays however). The big problem here isn't that you don't have a commit history. It's that these programs are often unbuildable. And often it seems that they are purposely distributed this way to deter other people from building or forking your software. Again however, I haven't actually checked the source files provided by 7zip in particular, but this problem I describe is a very common pattern in software whose source is distributed this way.