|Committed to Memory|
This quest is available during Post-Game from the Arsmith's Aleshouse Notice board. The quest requires you collect 10 pieces of Gran Soren Rubble which are scattered throughout what's left of Gran Soren.
There are several pieces on the rooftops of the Urban Quarter. There is also a bush in the craftsman's Quarter that you can gather some pieces from.
It's easier to acquire Gran Soren Rubble from The Slums area, which is destroyed after the dragon encounter, therefore it is recommended that you collect 10 and store them for later.
Reynard sells 8 of the Gran Soren Rubble.