https://en.wikipedia.org/wiki/Partial_zero-emissions_vehicleA partial zero emission vehicle, in the United States, is an automobile that has zero evaporative emissions from its fuel system, has a 15-year (or at least 150,000-mile) warranty on its emission-control components, and meets SULEV tailpipe-emission standards.
In California, PZEVs have their own administrative category for low-emission vehicles. The category was made in a bargain between automakers and the California Air Resources Board (CARB), so that automobile makers could delay making mandated zero-emission vehicles (ZEVs)—battery electric and fuel-cell electric vehicles.
The Super Ultra Low Emission Vehicle (SULEV) standard is more stringent than the Ultra Low Emission Vehicle and low-emission vehicle standards. All emissions-related components, including the electric-propulsion parts of hybrid electric vehicles, must be warranteed for 15 years or 150,000 miles. . . .
I don't remember if my 2003 Forester (the first year of the 2nd Gen.) pre-dated the standard or if they made changes to subsequent MY (or completed the 15 year/150k emissions cert late, as was the case with the Volt in its first year) so that it did, but mine lacks the PZEV badge, and later Foresters of the same generation have it.
As for the comment that Subaru is not a leader in fuel economy, they've been usually at or near the top of the list when it comes to AWD cars, despite not being HEVs, all of this with an R&D budget that's minuscule compared to say Toyota. None of which improves my opinion of the Crosstrek (P)HEV, as I remain unimpressed, but fair's fair.