The 3VA1163-4EF32-0KH0 is a Siemens SENTRON 3-pole molded case circuit breaker rated 63 A continuous at 40 °C, with a breaking capacity of 121 kA at 240 V — that's the short-circuit current it can safely interrupt without damage to upstream gear. At 415 V the breaking capacity drops to 75.6 kA, and at 690 V to 11.9 kA, so the voltage your line runs at directly governs which fault level this breaker can clear. Thermal derating is mild: the breaker holds 63 A up to 50 °C, then drops to 62 A at 55 °C, 61 A at 60 °C, 60 A at 65 °C, and 58 A at 70 °C (–). That means in a hot panel — say a steel-mill motor control center — you lose only 5 A from the 63 A rating at the 70 °C ceiling. That means you can wire remote status feedback and a remote trip command without adding external accessories — useful for emergency-stop circuits or PLC-based monitoring. No undervoltage release is fitted, so if your safety scheme requires undervoltage protection, that's a separate accessory.
The 70 mm depth means it fits in most 200 mm deep enclosures without interfering with the gland plate or door.