$ git clone -n https://src.fedoraproject.org/rpms/mumble.git /var/lib/mock/f45-build-19317-547/root/chroot_tmpdir/scmroot/mumble
Cloning into '/var/lib/mock/f45-build-19317-547/root/chroot_tmpdir/scmroot/mumble'...
$ git fetch origin 5a4f052bf46c5caf467ccf2883db5b92132ac486:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mumble
 * [new ref]         5a4f052bf46c5caf467ccf2883db5b92132ac486 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5a4f052 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild