There's been speculation on this about the Insight. I noticed this same phenomenon -- that the Insight CVT is shown not to have lean burn -- when I looked at the brochure.

I don't think that the software on the Insight for the CVT is that much different; it might be that the CVT puts some added "drag" on the engine, and you just don't go into lean burn much, if at all. That would explain some of why the CVT doesn't get as good gas mileage as its manual transmission counterpart. They (Honda) might have just decided to say that it doesn't have lean-burn, just to get around that fact.

If you translate this to the Civic Hybrid, with its bigger gas engine, it does have lean burn mode with CVT. It's been my experience, though, that the CVT doesn't enter lean-burn as often as a manual does, from my test drives. That's one reason I believe the manual gets slightly better mpgs than CVTs.

There's no indicator, however, that you are in lean-burn. Only the FCD (fuel consumption display, or instantaneous mpg meter) really shows it, by jumping 10-20 mpgs for no other reason (no downhill, foot off accelerator, etc). If you hold your foot steady on a flat road, you can actually "see" it cycle back and forth. At least, on mine you can.

Mark