That language means the inverter be listed as interactive-not the breaker. There is no requirement to fasten the breaker in this application.
The requirement to separately fasten a breaker has to do with whether or not the connected source could remain energized, after the breaker is pulled off the panel busbar. Such as when you use a branch breaker as a main breaker. Or if you interconnect a generator that could still energize the circuit if the rotor is still spinning. The safety issue of concern is that if you unplug the breaker from the busbar, that the energization could carry through to the busbar plugs of the stab-on breaker.
Grid-tied inverters don't work this way, because the inverter power source is subordinate to the voltage of the grid power source. The inverter looks for a grid within specification first, and then produces a slightly larger voltage to push current onto the grid. By design, the inverter ceases to produce power if the grid is disconnected. This wasn't considered when the rules for separately fastening a backfed breaker were first established, so a separate exception had to be written for grid-tied inverters.
Where you would still see this rule applied in a panel for grid-tied inverters, is a branch breaker as a main breaker of a subpanel combining your inverter outputs. Even though operational current flows through this breaker in the direction of an ordinary load breaker, the initial energization backfeeds it, and meets the physical basis for requiring this separate fastener.