Listers won't work to fetch metadata for all forges. On Github and on Bitbucket they don't get any metadata other than the description (and on Github, whether it's a fork). On GitLab they also get the number of stars and forks, but not much more.
We may want to use loaders for that, especially if we move away from the notion of having a single type/loader per origin.
Or have a new kind of component outside listers and loaders (eg. if we want to use Github's endpoint to list an org's repos like etalab does)