Custom SAMD51 Board (Add pins in variant files) Issue

[pert]

S1buell:
Where do I find this mapping "Since A6 is Arduino pin number 20 (14 + 6)"

Here:

S1buell:

#define PIN_A0               (14ul)

...

S1buell:

#define PIN_A6               (PIN_A0 + 6) //added

...

S1buell:

static const uint8_t A6  = PIN_A6; //added this line