$ git clone -n https://src.fedoraproject.org/rpms/rubygem-sugarjar.git /var/lib/mock/f42-build-side-1-3512335-46069/root/chroot_tmpdir/scmroot/rubygem-sugarjar
Cloning into '/var/lib/mock/f42-build-side-1-3512335-46069/root/chroot_tmpdir/scmroot/rubygem-sugarjar'...
$ git fetch origin 3dd9a5e2c36e53b4541afba9b79ce01e36020e0a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-sugarjar
 * [new ref]         3dd9a5e2c36e53b4541afba9b79ce01e36020e0a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3dd9a5e New upstream version 1.1.3