$ git clone -n https://src.fedoraproject.org/rpms/R-qtl.git /var/lib/mock/f39-build-2119509-50733/root/chroot_tmpdir/scmroot/R-qtl
Cloning into '/var/lib/mock/f39-build-2119509-50733/root/chroot_tmpdir/scmroot/R-qtl'...
$ git fetch origin a832a4b7fd6aec1ee929480cff64f69afe696751:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-qtl
 * [new ref]         a832a4b7fd6aec1ee929480cff64f69afe696751 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a832a4b Update to 1.66