I expect it refers to the proportion, weighted by filesize, of programs that are byte-for-byte reproducible across machines. (The assumption being that to take

I expect it refers to the proportion, weighted by filesize, of programs that are byte-for-byte reproducible across machines. (The assumption being that to take the same measurement in a dynamically-linked context would result in a number less than 100% due to machines having different copies of some libs.) In other contexts, it might simply be a proportion of whole packages, for example Arch Linux' core package set is 96.6% reproducible[1] (=256/(256+9)). The Linux kernel's lack of a stable ABI (specifically [2]; many userspace APIs are stabilised) doesn't mean individual revisions can't be built reproducibly. [1]: https://reproducible.archlinux.org https://reproducible.archlinux.org [2]: https://en.wikipedia.org/wiki/Linux_kernel#In-kernel_ABI https://en.wikipedia.org/wiki/Linux_kernel#In-kernel_ABI