$ git clone -n https://src.fedoraproject.org/rpms/libdnf.git /var/lib/mock/f40-build-807830-145288/root/chroot_tmpdir/scmroot/libdnf
Cloning into '/var/lib/mock/f40-build-807830-145288/root/chroot_tmpdir/scmroot/libdnf'...
$ git fetch origin fd0975985c56257cab091b7f34f127dd84ee087c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libdnf
 * [new ref]         fd0975985c56257cab091b7f34f127dd84ee087c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fd09759 Update to 0.73.1