Price of a confirmed swing high/low — a bar whose extreme beats strength bars each side.

Confirmation is lagging by design: a swing at bar N is not visible until bar N + strength, because the bars to its right have to print first. That is what makes it lookahead-free, and it means the newest readable swing is always at least strength bars old.

The comparison is strict, so a level matched exactly by a neighbouring bar never forms a swing. offset counts back through confirmed swings (0 = most recent); typed absence if that many have not been confirmed yet. A comparison over that absent operand is UNKNOWN; the action boundary takes no action.