$ git clone -n https://src.fedoraproject.org/rpms/kobo.git /var/lib/mock/f39-build-1841871-41995/root/chroot_tmpdir/scmroot/kobo
Cloning into '/var/lib/mock/f39-build-1841871-41995/root/chroot_tmpdir/scmroot/kobo'...
$ git fetch origin 35ca836b11d9f24de5e7bd2eab6d09fa01d2125c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kobo
 * [new ref]         35ca836b11d9f24de5e7bd2eab6d09fa01d2125c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 35ca836 rebase to latest upstream release