Hi, jcm!
The registration sequence is saved as part of the Registration Bank. If you do not configure a specific sequence, the default (12345678) will be saved. The registration sequence has a total of 32 slots, although you can use less. The sequence also stores the end-of-list behaviour, i.e., what to do when the end of the sequence is reached. The options are: STOP (just stay there), TOP (return to the first item in the sequence) or Next Bank (continue in the next Registration Bank).
If enabled, you can use a pedal to move (forward) in the set sequence. This can be very practical in complex music, where you need your hands on the keyboard, and need to change settings at the same time...
Regards!