Currently, the documention uses types like "unsigned long" (for example here: https://www.arduino.cc/en/Reference/millis). However, this is only correct for the AVR architecture, on e.g. the Due a long is (AFAIK) 64 bit, but the code explicity uses uint32_t. It would make sense to adopt the same explicit approach in the documentation (and, while we're at it, probably apply this to the code of the AVR port as well).