The service panel legend was incomplete. I noticed that the only 2 double circuits are in the panel. One was determined to be for electric stove, leading me to believe that this one pictured might be for the A/C. If so, according to the other picture of data plate, the circuit is “over-amped”. I am thinking the service conductor is 10g, and that is ok on 30 amp, correct?
You would need to open it to see if it contained 15 or 20 amp fuses the label doesn’t mean much. “Double circuit” breakers are called multipole or 2 pole CB’s