$ git clone -n https://src.fedoraproject.org/rpms/rgb.git /var/lib/mock/f45-build-34504-687/root/chroot_tmpdir/scmroot/rgb
Cloning into '/var/lib/mock/f45-build-34504-687/root/chroot_tmpdir/scmroot/rgb'...
$ git fetch origin cdc60c337442ac1de0b17272e0106c22d47ef209:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rgb
 * [new ref]         cdc60c337442ac1de0b17272e0106c22d47ef209 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cdc60c3 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild