$ git clone -n https://src.fedoraproject.org/rpms/legendary.git /var/lib/mock/f39-build-1978866-43337/root/chroot_tmpdir/scmroot/legendary
Cloning into '/var/lib/mock/f39-build-1978866-43337/root/chroot_tmpdir/scmroot/legendary'...
$ git fetch origin 515555d1840f8d9fb821ca37b311ddfd72970c16:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/legendary
 * [new ref]         515555d1840f8d9fb821ca37b311ddfd72970c16 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 515555d [packit] 0.20.34 upstream release