Fedora change aims for 99% package reproducibility

"given the same source code, build environment and build instructions, any party can recreate bit-by-bit identical copies of all specified artifacts"

NixOS does not guarantee bit-by-bit identical results. NixOS hashes the inputs and provides a reproducible build environment but this does not necessarily mean the artifacts are identical.

E.g. if a build somehow includes a timestamp, each build will have a different checksum.