The 125 A rating holds flat from 40 °C through 50 °C, then derates to 120 A at 55 °C, 117.5 A at 60 °C, 115 A at 65 °C, and 112.5 A at 70 °C. Breaking capacity is 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V. The auxiliary contact package is 2 HQ (high-quality) switches, which is enough for a remote status signal but not for complex interlocking. If you need an undervoltage release or ground-fault alarm, you're looking at a different variant in the 3VA family.
That 76.2 mm width is three 25.4 mm pole modules — standard for a 3-pole MCCB in a distribution board.
The closest sibling in the 3VA family is the 3VA1112-5EF32-0CA0. Both are 125 A, 3-pole, TM240 breakers with the same dimensions and the same breaking capacities. The difference is the auxiliary contact count: this -4EF32 carries 2 HQ switches; the -5EF32 carries 1 HQ switch plus 1 alarm switch. If your panel wiring expects a separate alarm contact for the trip signal, the -5EF32 saves you an external auxiliary block. If you only need a single status feedback, either works — the -4EF32 gives you a spare contact for future use. Footprint is identical, so no rewiring or busbar rework if you swap between them.