CVTF: Continuous variable transmission fluid for CVT gearbox, all honda city's from 3G to 4.5 G have this, other popular cars that have this is honda insight and mitsu lancer, construction wise CVT gearbox is the cheapest and simplest.

ATF is the automatic transmission fluid for auto gearboxes with proper gears. Note that City CVT does not have proper gears. Google for CVT gearbox as its a very complex topic to explain without a diagram...