$ git clone -n https://src.fedoraproject.org/rpms/libxshmfence.git /var/lib/mock/f40-build-2008928-45428/root/chroot_tmpdir/scmroot/libxshmfence
Cloning into '/var/lib/mock/f40-build-2008928-45428/root/chroot_tmpdir/scmroot/libxshmfence'...
$ git fetch origin 3e6777f09c4e16ab84c63294a87aba395b955c83:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libxshmfence
 * [new ref]         3e6777f09c4e16ab84c63294a87aba395b955c83 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3e6777f libxshmfence 1.3.2