I could not find the one on their site for the Rocket, but this is what it says for a Suzuki, mine says the same thing about timing, so I copied and pasted it here.
Built-in Advanced TRE
Suzuki EFI bikes use different ignition timings in each gear to conform to local regulations for
noise and emissions. As a result, ignition timings are retarded in lower gears.
With activated TRE (Timing Retard Eliminator) both throttle response and acceleration are
improved in gears 1 through 4. Also, the bike's top speed limiter will be disabled on GSXR1000,
GSX1300R, DL1000 and M109R models. (Note: Using a TRE does not add more HP at full
throttle.)
Even if TRE is activated, it automatically switches off in Neutral for smooth idle operation.
By the touch of a button on the GIpro, the rider can switch instantly between four modes:
Off, 4th Gear Map, 5th Gear Map and 6th Gear Map.
There is visual confirmation of the selected mode.
If a TRE device is installed on a bike equipped with OEM gear indicator, the bike’s indicator
becomes useless. However, the GIpro will indicate the gear selected regardless whether the
built-in TRE is activated or not.
To comply with local regulations, do not activate TRE mode on public roads.
Native One