Comment by falcor84
> rebuild it from scratch
That's beyond the definition of Open Source. Doing a bit of license research now, only the GPL has such a requirement - GPLv3:
> The "Corresponding Source" for a work in object code form means all the source code needed to generate, install, and (for an executable work) run the object code and to modify the work, including scripts to control those activities.
But all other Open Source compliant licenses I checked don't, and just refer to making whatever is in the repo available to others.
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"