$ git clone -n https://src.fedoraproject.org/rpms/m1n1.git /var/lib/mock/f41-build-849394-164774/root/chroot_tmpdir/scmroot/m1n1
Cloning into '/var/lib/mock/f41-build-849394-164774/root/chroot_tmpdir/scmroot/m1n1'...
$ git fetch origin 1b275ee89f9d2e6fdb2a24c7f0f2af6da57defa7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/m1n1
 * [new ref]         1b275ee89f9d2e6fdb2a24c7f0f2af6da57defa7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1b275ee Update to 1.4.15