The ABB XT2LU3100BFF00NXXX is a molded case circuit breaker from the XT2L series, carrying the description XT2L 125TMA 100-500-1000 3PFFUL/CSA. The 125TMA designation points to a thermal-magnetic trip unit with a 100 A continuous rating and adjustable magnetic trip from 500 to 1000 A — the range you'd set for motor inrush or feeder coordination. The 3PFFUL/CSA suffix confirms three-pole construction with line/load terminals and UL/CSA certification, so it's accepted in North American panels without a separate approval step.
The 3PFFUL/CSA terminals accept copper or aluminum conductors, and the UL listing means the SCCR is validated for North American fault levels without derating.