It was a lounge area. Basically, there were sofas mounted sideways along the cabin sidewall, on both sides of the cabin. Since the fuselage was tapered, they made something of a V shape -- very intimate. When the L188 was used for two-class service, it served as a lounge for F class pax, who occupied seats in the area right behind the galley. Later, as more of them became all-coach, the rear lounge could be occupied by anyone, and if they were fitted with shoulder harnesses, could be occupied at takeoff and landing. I did just that on an Air California L188 from Tahoe to SFO.