The 5SV4444-0LA: The 40 A rating holds flat across the full ambient range (-25 °C to +45 °C operating, derated to 70 °C storage), so no thermal derating curve to calculate for a standard panel environment. The 100 mA residual trip is a common choice for equipment protection (not personnel shock protection, which typically uses 30 mA) — it's sized to catch insulation faults on feeders or large loads without nuisance tripping from normal leakage.
Depth is 70 mm, same as the installation depth, so it sits flush with the front of a standard distribution board.