W3C operates this GitHub organization to host repositories from Community Groups - see Community Groups Tools and Infrastructure.
CG repos in this organization get created by the W3C CG Team (team-community-process@w3.org) when asked by the Chair(s) of a Community Group.
CGs can get a repo based on their shortname. If the group needs multiple repos, additional repos prefixed with that shortname can also requested, although if a Community Group expects to need many different repos, the Community Group might consider creating and operating its own GitHub organization.
By default, the repos get configured with the Chairs (when their GitHub accounts is known) being granted "maintainer" rights on the repos. Chairs can request support from the W3C CG Team at team-community-process@w3.org to add and modify these rights.