Number: 99 (coarse) 98 (fine)
Which parameter the Data Button Increment, Data Button Decrement, or Data Entry controllers affect. Since NRPN has a coarse/fine pair (14-bit), the number of parameters that can be registered is 16,384. That's a lot of parameters that a MIDI device could allow to be controlled over MIDI. It's entirely up to each manufacturer which parameter numbers are used for whatever purposes. These don't have to be registered with the MMA.
The same scheme is used as per the Registered Parameter controller. Refer to that. By contrast, the coarse/fine messages for NRPN for the preceding RPN example would be:
B0 63 00 B0 62 01Note: Since each device can define a particular NRPN controller number to control anything, it's possible that 2 devices may interpret the same NRPN number in different manners. Therefore, a device should allow a musician to disable receipt of NRPN, in the event that there is a conflict between the NRPN implementations of 2 daisy-chained devices.