$ git clone -n https://src.fedoraproject.org/rpms/mathicgb.git /var/lib/mock/f40-build-774019-127559/root/chroot_tmpdir/scmroot/mathicgb
Cloning into '/var/lib/mock/f40-build-774019-127559/root/chroot_tmpdir/scmroot/mathicgb'...
$ git fetch origin 67705f7a8a2e3f23e63c3b9d082a67d948de457f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mathicgb
 * [new ref]         67705f7a8a2e3f23e63c3b9d082a67d948de457f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 67705f7 Update to latest upstream snapshot