$ git clone -n https://src.fedoraproject.org/rpms/nemo-extensions.git /var/lib/mock/f40-build-2140880-50850/root/chroot_tmpdir/scmroot/nemo-extensions
Cloning into '/var/lib/mock/f40-build-2140880-50850/root/chroot_tmpdir/scmroot/nemo-extensions'...
$ git fetch origin 9777428eea447775f0c52fc2d48a350cc624163e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/nemo-extensions
 * [new ref]         9777428eea447775f0c52fc2d48a350cc624163e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9777428 fix