$ git clone -n https://src.fedoraproject.org/rpms/maven-mapping.git /var/lib/mock/f40-build-1063421-19507/root/chroot_tmpdir/scmroot/maven-mapping
Cloning into '/var/lib/mock/f40-build-1063421-19507/root/chroot_tmpdir/scmroot/maven-mapping'...
$ git fetch origin 6a257c3a3cce19f0ebfa269bdf079447427f0f06:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/maven-mapping
 * [new ref]         6a257c3a3cce19f0ebfa269bdf079447427f0f06 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6a257c3 Set maven java source and target to 1.8