$ git clone -n https://src.fedoraproject.org/rpms/kf6-kxmlgui.git /var/lib/mock/f42-build-side-1-3573612-46768/root/chroot_tmpdir/scmroot/kf6-kxmlgui
Cloning into '/var/lib/mock/f42-build-side-1-3573612-46768/root/chroot_tmpdir/scmroot/kf6-kxmlgui'...
$ git fetch origin f665835c781bc22b5189d92bd4d371672ec14ea6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kf6-kxmlgui
 * [new ref]         f665835c781bc22b5189d92bd4d371672ec14ea6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f665835 6.15 and plasma 3.4 compatibility rebuild