Do the names on the silkscreen have numbers? I'd try using the numbers.
You can find the pin definitions in:
hardware/samd/1.8.11/variants/mkr1000/pins_arduino.h
which contains nothing but an include for:
hardware/samd/1.8.11/variants/mkr1000/variant.h
which starts with an include for:
hardware/samd/1.8.11/cores/arduino/WVariant.h