The Xfce repositories¹⁾ are automatically mirrored on GitHub.

Go to the git.xfce.org mirror @ GitHub.

No, they won't be accepted. Issues have been disabled already while pull requests can't be removed on a per-organization basis but still the Xfce maintainers and developers will keep using the current workflow for reviewing and eventually accepting patches coming from GitHub's users. Use the bug tracker to upstream modifications.

The mirrors are only there for backup and to make forking for users easier.

Modules are created and updated on-the-go when a change gets pushed to a repository.