you can slap a hash on a binary distribution and it becomes "reproducible" in the same trivial sense as any source tarball. after that, the reproducibility of whatever "build process" takes place to extract archives and shuffle assets around is no more or less fraught than any other package (probably less considering how much compilers have historically had to be brought to heel, especially before reproducibility was fashionable enough for it to enter much into compiler authors' consideration!!)