Its ACEA A3/B4
The CLASS indicates oil intended for a general type of engines – currently there are:
A/B = Gasoline and Light Duty Diesel Engines
C = Catalyst compatible oils for Gasoline and Light Duty Diesel Engines with Aftertreatment devices
E = Heavy Duty Diesel Engines Other classes may be added in future if, for example, Natural Gas Engines may prove to require oil characteristics which cannot readily be incorporated into existing classes.
So as it's A3/B4. Does that mean it's designed for older vehicles, possible pre 1975? Would not the "C" class be better for gasoline engines with catalytic converters and diesels with diesel particulate filters?