$ git clone -n https://src.fedoraproject.org/rpms/harfbuzz.git /var/lib/mock/f41-build-side-1-2805888-32866/root/chroot_tmpdir/scmroot/harfbuzz
Cloning into '/var/lib/mock/f41-build-side-1-2805888-32866/root/chroot_tmpdir/scmroot/harfbuzz'...
$ git fetch origin df50620628aceb95a40924eb67d11a153a2e06c9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/harfbuzz
 * [new ref]         df50620628aceb95a40924eb67d11a153a2e06c9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at df50620 Upstream renamed README to README.md