I have Siemens QP breakers, but I believe this generalizes well.
Let's take the QP breakers as an example:
There are some temperature ratings marked on it where it reads
CU-AL 60/75°C WIRE
Why are two temperature ratings indicated? Is it simply to indicate compliance with either 60°C usage cases (ex. NM-B) or 75°C usage cases (ex. THWN)? Does it depend on whether the wire is copper or aluminum (ex. 60C for Cu and 75°C for Al)?