$ git clone -n https://src.fedoraproject.org/rpms/polkit.git /var/lib/mock/f39-build-1445890-32653/root/chroot_tmpdir/scmroot/polkit
Cloning into '/var/lib/mock/f39-build-1445890-32653/root/chroot_tmpdir/scmroot/polkit'...
$ git fetch origin ffe032f46292963f937e596348f61fbb8f5cf033:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/polkit
 * [new ref]         ffe032f46292963f937e596348f61fbb8f5cf033 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ffe032f Rebase to v.123