$ git clone -n https://src.fedoraproject.org/rpms/libunwind.git /var/lib/mock/f38-build-side-42-init-devel-603532-26220/root/chroot_tmpdir/scmroot/libunwind
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-603532-26220/root/chroot_tmpdir/scmroot/libunwind'...
$ git fetch origin 027f854d2dc87284c7fc76abf10a2fdd94ed020a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libunwind
 * [new ref]         027f854d2dc87284c7fc76abf10a2fdd94ed020a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 027f854 disable tests on s390x (reported upstream: https://github.com/libunwind/libunwind/issues/464)