The 75.6 kA breaking capacity at 240 V (52.5 kA at 415 V, 32 kA at 440 V, 7.5 kA at 500 V and 690 V) tells you the maximum fault current it can safely interrupt at each voltage level.
The 80 A rating holds from 40 °C through 50 °C, then derates to 78 A at 55 °C, 77 A at 60 °C, 75 A at 65 °C, and 74 A at 70 °C. The 70 mm depth, 101.6 mm width, and 130 mm height fit a standard DIN-rail or panel-mount footprint; the 21.7 W maximum power loss needs to be factored into the enclosure's thermal budget.