$ git clone -n https://src.fedoraproject.org/rpms/magma.git /var/lib/mock/f41-build-side-1-3099410-39334/root/chroot_tmpdir/scmroot/magma
Cloning into '/var/lib/mock/f41-build-side-1-3099410-39334/root/chroot_tmpdir/scmroot/magma'...
$ git fetch origin 5952a0c450e155fce11210af249a95cec45ef120:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/magma
 * [new ref]         5952a0c450e155fce11210af249a95cec45ef120 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5952a0c Rebuild