$ git clone -n https://src.fedoraproject.org/rpms/sid.git /var/lib/mock/f40-build-2645139-66535/root/chroot_tmpdir/scmroot/sid
Cloning into '/var/lib/mock/f40-build-2645139-66535/root/chroot_tmpdir/scmroot/sid'...
$ git fetch origin 07ec2977415e5f9f601bb2b894736874e8c7e68d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/sid
 * [new ref]         07ec2977415e5f9f601bb2b894736874e8c7e68d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 07ec297 Update to latest upstream release v0.0.6.