Another- (RENO) we must know other codes.

Local ordnance,via 'sewer commission': Septic ejection/grinder MUST have provisions for generator hook up.

#1 I feel this is a way over step !!!!!!!!!!!!!!
Another design issue causing undo expense to the home owner/seller.Thus influencing my Competitive bid.

#2 My plan: 23A-120/250V 1 Phase-4-wire
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Install in the control cabinet: A male L14/30 - on the bottom.
then install a WP female wip cord cap.

The end result: cord & plug for disconnect,and a male recept. for the gen set cord.

After that- your problem.
No requirement that home owner HAS generator- just that 'provisions ' are made.

Any problems? My local pros think not.