I am referring to this kind of hammer, also known as a roofing hammer.
I understand that the flat end is intended to act as a normal hammer, and the sharp end is intended to pierce holes through roofing slate, to aid in fastening (perhaps by nails)
However, what is the purpose of the non-sharp protrusion from the rear (non-hammer) end? In other words, why is the roofing hammer's rear end asymmetric?
-edit- I found another roofing hammer, which clearly has the two rear protrusions offset from one another, so it is unlikely to be for the purpose of being a nail claw. Anyone has experience with one of those, then?