How is ArduinoCore-avr/wiring.c at master · arduino/ArduinoCore-avr · GitHub
And nearby code not what you’re looking for? It tells you about the pwm mode ,tells you what the prescalers will be, and has the other bits needed called out as well. True, it doesn’t decried all the bits left off, but that’s rarely done outside of tutorials and class assignments for especially fussy profs. (And it becomes rapidly impractical on even moderately complex peripherals. You are expected to use both code and data book to fully understand.