Meaning of symbol with three peaks and numerical value on PSU?
It's an altitude restriction, saying that it's only certified for use at altitudes less than 2000 meters. The symbols aren't very standard, so each manufacturer is free to decide how to convey that information. 

There is some component inside that is not tested above that altitude, I'm not sure if that is due to the capacitors, or some other component, or due to spacing of the traces on the PCB and the current carrying abilities, etc.