The 10 kA breaking capacity at 400 V AC tells you it can safely interrupt a fault current up to 10,000 A without welding contacts or cascading upstream, which is the typical SCCR for commercial panelboards in a 400 V distribution system.
Deployment context and panel fit
Snap-on DIN rail mount, 4-pole wide (72 mm at 18 mm per pole). Standard for a 400/415 V three-phase plus neutral distribution board. The B-curve characteristic means it holds through the brief inrush of a contactor coil or a bank of LED drivers, but clears fast on a hard short. Product class B on this listing means return-restricted — if you are stocking this for a line, make sure your procurement knows the return policy before ordering multiples.