Nixpkgs is a whole collection of software (a distribution of sorts, but not a Linux distro), managed by Nix, which works identically on all Linux distros. It's

Nixpkgs is a whole collection of software (a distribution of sorts, but not a Linux distro), managed by Nix, which works identically on all Linux distros. It's also the package collection for NixOS. Nix is cross-distro in the ordinary sense you describe, of course. It is also more deeply cross-distro in that: • if you are trying to package for Nix in a normal way (the tools make it easy to do things this way and hard to do things otherwise by their nature), _all_ package collections for Nix will be cross-distro in this way • The Nix community has a collection of thousands of cross-distro packages you can already use right now `pkgsrc` is similar in this respect, and takes a more conventional approach, like the one you describe in this comment. I think that's a meaningful sense in which it is cross-distro. Another way to think of this is that tools like `rpm` and `dpkg` or `dnf` and `apt` are portable between distros _as far as distro developers are concerned_, whereas package managers/package collections like Nixpkgs and pkgsrc meet the portability needs of users of _existing distros_.