The tunnels are inhabited by a large number of mole rats and raiders. Both types of vermin are connected to an amateur scientists named Ryan Brigg. He reluctantly joined forces with the raiders to further his research into creating better tasting mole rat meat, which could be a cheap source of sustenance for most wastelanders.
His lengthy experiments led to agitating the local mole rat population, as they required an extensive supply of raw meat. The raiders don't mind and see Brigg as their informal leader, as he pays them for any meat they bring.
The sole exception is Pumpkin, is a tame mole rat Ryan Brigg keeps as a pet inside his laboratory.
The tunnels are extensive and have plenty of winding tunnels and small utility rooms. They are particularly rich in terms of low level loot. One of the most abundant items is, obviously, mole rat meat and wonderglue, which can be readily converted into wonder meat in Brigg's laboratory.