$ git clone -n https://src.fedoraproject.org/rpms/Thunar.git /var/lib/mock/f39-build-1579840-38043/root/chroot_tmpdir/scmroot/Thunar
Cloning into '/var/lib/mock/f39-build-1579840-38043/root/chroot_tmpdir/scmroot/Thunar'...
$ git fetch origin a4bfc0e9d141889c6fcb66968a91aebcef97bb9f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/Thunar
 * [new ref]         a4bfc0e9d141889c6fcb66968a91aebcef97bb9f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a4bfc0e Update to v4.18.7