$ git clone -n https://src.fedoraproject.org/rpms/ruby-build.git /var/lib/mock/f39-build-1457971-33028/root/chroot_tmpdir/scmroot/ruby-build
Cloning into '/var/lib/mock/f39-build-1457971-33028/root/chroot_tmpdir/scmroot/ruby-build'...
$ git fetch origin 38b2d6b2eb0808dd72562c5fd056c49ebdc2de78:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ruby-build
 * [new ref]         38b2d6b2eb0808dd72562c5fd056c49ebdc2de78 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 38b2d6b Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild