$ git clone -n https://src.fedoraproject.org/rpms/jaxb-istack-commons.git /var/lib/mock/f38-build-side-42-init-devel-608795-26260/root/chroot_tmpdir/scmroot/jaxb-istack-commons
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-608795-26260/root/chroot_tmpdir/scmroot/jaxb-istack-commons'...
$ git fetch origin 1f4a29fbfe9a501fa1894c2da3cda59ace35493d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jaxb-istack-commons
 * [new ref]         1f4a29fbfe9a501fa1894c2da3cda59ace35493d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1f4a29f Reorganize subpackages