$ git clone -n https://src.fedoraproject.org/rpms/rust-afterburn.git /var/lib/mock/f41-build-1099117-20020/root/chroot_tmpdir/scmroot/rust-afterburn
Cloning into '/var/lib/mock/f41-build-1099117-20020/root/chroot_tmpdir/scmroot/rust-afterburn'...
$ git fetch origin b90842b5ae7b36fc2c8b5a2e9efd6eaafb6a88a7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-afterburn
 * [new ref]         b90842b5ae7b36fc2c8b5a2e9efd6eaafb6a88a7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b90842b 5.6.0