$ git clone -n https://src.fedoraproject.org/rpms/erlang-cowboy.git /var/lib/mock/f41-build-side-1-2893051-34611/root/chroot_tmpdir/scmroot/erlang-cowboy
Cloning into '/var/lib/mock/f41-build-side-1-2893051-34611/root/chroot_tmpdir/scmroot/erlang-cowboy'...
$ git fetch origin e79805f79066d867c2635e7e2532ac2943019a8b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/erlang-cowboy
 * [new ref]         e79805f79066d867c2635e7e2532ac2943019a8b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e79805f Added missing BR but tests are still broken