$ git clone -n https://src.fedoraproject.org/rpms/appstream-data.git /var/lib/mock/f39-build-1624450-39060/root/chroot_tmpdir/scmroot/appstream-data
Cloning into '/var/lib/mock/f39-build-1624450-39060/root/chroot_tmpdir/scmroot/appstream-data'...
$ git fetch origin 9f4d79b960168ab38c2cce999c31c4ef527f5949:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/appstream-data
 * [new ref]         9f4d79b960168ab38c2cce999c31c4ef527f5949 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9f4d79b New upstream release