The answer is unfortunately that they are not especially similar, you can compare the two:

• https://github.com/arduino/ArduinoCore-samd/blob/master/variants/mkrzero/variant.cpp
• https://github.com/arduino/ArduinoCore-samd/blob/master/variants/arduino_zero/variant.cpp

However adding the mapping between board pins and chip pins shouldn't be too bad, it would look extremely similar to the mkrzero one but with the values from arduino_zero sheet above.

Nice, this doesn't look too difficult to implement. When I have a minute, I'll do it - cheers. I'll leave this open until then.