I recently added a new endpoint: /channel/:channel
It gives you a slightly nicer way of using the channels.nixos.org tarballs (which are a good bit smaller than the GitHub equivalents) in your Flakes, like this:
{
inputs.nixpkgs.url = "https://nixpkgs.dev/channel/nixos-unstable";
}
And thanks to @emilylange for originally adding support for this upstream in mirror-nixos-branch: add header for "Lockable HTTP Tarball Protocol" (Flakes) by emilylange · Pull Request #76 · NixOS/nixos-channel-scripts · GitHub 