$ git clone -n https://src.fedoraproject.org/rpms/mm-common.git /var/lib/mock/f45-build-18986-539/root/chroot_tmpdir/scmroot/mm-common
Cloning into '/var/lib/mock/f45-build-18986-539/root/chroot_tmpdir/scmroot/mm-common'...
$ git fetch origin 03547f03e96d9b2adb973cfb797c644173a09ad6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mm-common
 * [new ref]         03547f03e96d9b2adb973cfb797c644173a09ad6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 03547f0 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild