What if I want to be able to do something like this in flakeB:

{
  inputs.flakeA.url = "/path/to/flakeA";
  outputs = inputs: inputs.flakeA ./. { inherit inputs; };
}

in flakeA, I did something like this:

{
  inputs = {...};
  outputs = inputs:
    flakelight ./. {
      imports = [
        flakelight.flakelightModules.flakelightModule
        ./myfeature.nix
      ];
      flakelightModule = {lib, ...}: {
        imports = [./myfeature.nix];
        inputs.flakelight = lib.mkDefault flakelight;
        inputs.home-manager = lib.mkDefault home-manager;
     };
   };
}

If you are using both NixOS and Home Manager, is it supported to use the homeConfigurations like this in a nixosModule?

home-manager.users.${username} = inputs.self.homeConfigurations.${username}

I get the following error, when I try it:

 Module `:anon-5:anon-1' has an unsupported attribute `activation-script'. This is caused by introducing a top-level `config' or `options' attribute. Add configuration attributes immediately on the top level instead, or move all of them (namely: activation-script activationPackage extendModules newsDisplay newsEntries pkgs) into the explicit `config' attribute.