$ git clone -n https://src.fedoraproject.org/rpms/alex.git /var/lib/mock/f40-build-1990431-43409/root/chroot_tmpdir/scmroot/alex
Cloning into '/var/lib/mock/f40-build-1990431-43409/root/chroot_tmpdir/scmroot/alex'...
$ git fetch origin 1bffbe9c6d956497f3fa1eee7a82ce1d46ff8775:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/alex
 * [new ref]         1bffbe9c6d956497f3fa1eee7a82ce1d46ff8775 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1bffbe9 https://hackage.haskell.org/package/alex-3.3.0.0/changelog