Same as the initial, the examiner will likely give you the long brief topic in advance so you can prepare any board notes or whatever, then you just brief away.
The typical topic I was given was factors which affect the stall speed, but you could equally be expected to give a brief on any topic, some other examples I've heard of are overhead joins, different types of airframe/intake icing, PFLs, the list is probably endless.
A long brief is typically planned for 20-30 mins, and on my initial and subsequent renewal the examiner cut me off after about 10 mins, said they got the jist of where I was going, asked a few follow up questions, and we moved on.