Example
A bullish FVG from 103.2 to 104.1 has its CE at 103.65.
In practice
The midpoint gives a fair value gap a line to be judged by. If price returns to a bullish gap and closes hold above its midpoint, the gap is doing its job. Closes below it suggest the gap is failing.
Some traders place limit entries at the midpoint instead of at the edge of the gap, accepting fewer fills in exchange for a better price and a smaller stop.
What to watch for
Price often turns at the edge of a gap without ever reaching the midpoint, so waiting for it means missing trades. A wick through the level matters less than where candles close.