How do I read circuit breaker temperature ratings?
60/75°C Wire — All circuit breakers rated 125 A or less are marked for use with 60° C, 60/75°C or 75°C only wire. This marking indicates the proper wire size for termination in accordance with Table 310.15(B)(16) of the NEC . It is acceptable to use wire with a higher insulation rating if the ampacity is based on the wire temperature rating marked on the breaker. For breakers rated more than 125 A, the proper wire temperature rating is 75°C and it is optional for the breaker to bear this marking. 

REF: UL Marking and Application Guide - Molded Case Circuit Breakers 2016 Page 10 Terminations (20)