It is 1 1/2" wide skewed rabbet bedded at 45 degrees.
I recently saw a thread on some woodworking forum regarding iron skew angles versus, due to complex angles, the angle at which the teeth of a float should be sharpened.
The float I use for the bed of the plane is skewed at 10(ish) degrees. For the front I use a float at a light 12. This resulted in a bed angle of a heavy 15 degrees, with 15 being the original goal.