This is a most unusual structure, and it is not certain that it was a World War 2 Pillbox. It is triangular in shape, with a narrow front facing downhill. There is a window (loophole) in this wall, which is about 8-inches thick. The structure then fans out slightly towards the rear.
It is suspected that this was an machine gun emplacement, or possibly a light gun. The thick Westwards facing frontage and apparent loophole give it the definite appearance of a defence position. On a much smaller scale, there is a similar shaped emplacement on the roof of Support Defence Post L17 near Zonkor, which was apparently for a Boys Anti Tank Rifle.