Rated current is 3 A at 35 °C ambient, but the datasheet provides a full derating curve: 2.88 A at 40 °C, 2.82 A at 45 °C, 2.76 A at 50 °C, 2.69 A at 55 °C, and 2.63 A at 60 °C. The B-curve's magnetic trip at 3–5× In means it will clear a hard short quickly, but it may nuisance-trip on the capacitor inrush of a small power supply if the supply is oversized relative to the 3 A rating.
The combined terminal design accepts top and bottom feed, and the supply cord position is any — no orientation restrictions for the line/load side. The 76 mm depth includes the breaker body; the 90 mm height is the overall profile including the toggle and terminals.