CKAN, the package manager for Kerbal Space Program mods, works by having a central metadata repo that they accept pull requests against for adding metadata for

CKAN, the package manager for Kerbal Space Program mods, works by having a central metadata repo that they accept pull requests against for adding metadata for new mods, and then the mods themselves are hosted on Github or SpaceDock or wherever. It's not quite as automated as publishing a NPM or Composer package, but it's close and works well.