This flake contains all of my public github flakes as outputs. It means that I don’t have to specify many inputs for my flakes, just this one! For my system flake, I have as an input:
inputs.flakes.nix = github:jeslie0/flakes;
Then, if I want to use the swaybgchanger output for instance, I do something like this in my configuration.nix file:
environment.systemPackages = with pkgs;
[ ...
self.inputs.flakes.swaybgchanger.defaultPackage.${system};
...
];