Howdy folks,
I'm trying to understand how USB works as a whole [for implementing Devices]. Currently, I'm trying to dive through the teensy4 usb.c code, but I'm having trouble interpreting it.

In usb.c, "Device Controller Initialization, page 3161" is referenced[1]. Where can I find the document that this is referencing? I'm not familiar with where USB specifications live.

Many Thanks,