I feel sometimes like package management is a relatively second-class topic in computer science (or at least among many working programmers). But a package manager's behavior can be the difference between a grotesque, repulsive experience and a delightful, beautiful one. And there aren't quite yet any package managers that do well everything that we collectively have learned how to do well, which makes it an interesting space imo.

Re: Nixpkgs, interestingly, pre-flakes Nix distributes all of the needed Nix expressions as tarballs, which does play nice with CDNs. It also distributes an index of the tree as a SQLite database to obviate some of the "too many files/directories" problem with enumerating files. (In the meantime, Nixpkgs has also started bucketing package directories by name prefix, too.) So maybe there was a lesson learned here that would be useful to re-learn.

On the other hand, IIRC if you use the GitHub fetcher rather than the Git one, including for fetching flakes, Nix will download tarballs from GitHub instead of doing clones. Regardless, downloading and unpacking Nixpkgs has become kinda slow. :-\

Or does fossil itself still have the same issues ?