An order block on gold is the candle range from which an aggressive move originated, later used as a reference zone where price may react on a pullback. The defensible reading is that a sharp departure from a level indicates a supply and demand imbalance there, and that participants who missed the initial move tend to act when price returns, which makes reactions more frequent than at random prices.
The claim that unfilled institutional orders still sit inside the box cannot be observed from a retail XAUUSD chart. To make the concept testable a trader must fix the zone boundary, defining timeframe, entry trigger and invalidation in advance, then measure the outcome across a gold-specific sample rather than redrawing the zone after the fact.