Every client of the match reports the result, not just the host: in a 1v1 both peers send reportMatch with the same match_id. A server that stores or rates the match has to be idempotent per match_id (our implementation applies the Elo change only on the first report and ignores the duplicates).
results uses 1 for the winner and 0 for the loser, aligned by index with profile_ids.
The response contains the replay upload target; a local server can return the same shape with empty strings when replays are not supported.