Might just be a really nifty place for a shop technician to connect a vacuum gage to check filter restriction and adjust idle mixture based on vacuum, or an easy/quick way to hit the engine with starter fluid without removing the filter. Not much compensation from mechanical injectors, and very little real engine/emissions management going on with the ECU. That's mostly display stuff. But I do like the idea of a gage to tell me when the filter actually needs changing, though. Coming up on my 200H service soon, and only because warranty says so, I'll be changing the air filter then. Still looks nearly brand new, but most of my run time is either sitting still with the chipper going, or on damp/low dust soil under tree canopy. I wouldn't be surprised if humidity had its own effect on the filters, and if there's one thing we have plenty of in Central Alabama, it's humidity. I can see where a venturi effect of humid air going through the filter would cause moisture to condense in it.