The 3 kA breaking capacity, certified under both EN 60898 and IEC 60947-2, tells you it can safely interrupt a fault current up to 3,000 A at 400 V AC. For a panel fed from a transformer or a sub-distribution board with a modest fault level, that's adequate. Overvoltage category 3 means it's rated for fixed-installation use — think permanent wiring in a distribution board, not plug-in gear.
The neutral conductor is switched, which is a detail worth noting: on a 2-pole breaker that switches both live and neutral, you get full isolation on the outgoing circuit. That matters for maintenance lockout on a 230 V single-phase line where you want both poles opened.