Jet Tub wireing

Hello
redoing my bathroom and came across the pump for my jet tub .... my question is the ground on the outside of the unit is not attached to any thing did a little reasearch and found this page... https://terrylove.com/jet.htm
about half way down it says that that should be attached to "proper equiment grounding condutor" can some one help me out so i understand what that means? i do know the inside ground is hook up as i opened the cover to check.

Well whatever instructions those are they are wrong.
The external lug is NOT for grounding, it is for bonding.

The bond required in NEC 680.74 is attached there.

This is from the 2005 NEC:
680.74 Bonding
All metal piping systems and all grounded metal parts in contact with the circulating water shall be bonded together using a copper bonding jumper, insulated, covered, or bare, not smaller than 8 AWG solid.

The lug on the motor is for bonding to such items as water pipes or other metal used in the installation of the tub.

The equipment grounding conductor is supplied with the branch circuit and does not need to land on this lug