Yes, you can see UL & CSA labels on breaker in that package photo.
Can you elaborate how that changes things?
Someone should probably make this issue a "sticky", it comes up a lot here.
Circuit breakers that plug into or bolt directly onto a load center or panelboard bus bar must be specifically listed in combination with each and every load center / panelboard it is to be used with. These are destructive tests and they are expensive. The manufacturer of the panel will, as you might imagine, ONLY test their panels with their own breakers, they have ZERO incentive to test competitor's products, nor are they inclined to provide warranty coverage for a panel in which competitor's breakers are installed. These issues of course mean nothing when it comes to equipment that is already installed and past any warranty periods. So that's where the concept of "Classified Breakers" comes in.
Classified Breakers are the UL way of legitimizing an earlier concept often referred to an "interchangeable breakers"; essentially quasi-listing breakers made by one manufacturer for use in a panel made by another. In that process, the manufacturer of the BREAKER pays for the testing of their Classified Breaker in the panels made by their competitors. They literally buy one from a distributor and plug their classified breakers into them, then blow them up. THEY then bear the cost of these testes and absorb that into the cost of their classified breakers.
In that process, they must test their Classified Breakers in EVERY version of a competitor's panels that they want to cover. So if Connecticut Electric wants their breakers listed in Siemens panels, they must attain and test EVERY possible combination of Siemens panels that would likely work. In reality, that is way too expensive and what they do is pick out the high volume or the latest versions. They will save cost by ignoring the oldest or fringe versions, anything where their return on investment in the testing is not likely to result in enough sales to justify it. So when you open that blister pack, there is a little folded list of very specific panels that these Classified Breakers are classified to work with. It is
your responsibility to ensure that your panel is on that list, and you will get zero help from the panel manufacturer if there is a question about that. Some AHJs can be real sticklers for this issue, others accept it as a fact of life, but you never know what someone will say unless you've dealt with that AHJ before.
Another "gottcha" is if your panel had a "series rating" on it, i.e. if you used a Siemens panel with a specific main breaker or it is protected by a specific upstream fuse, the 10kAIC rated branch breakers in your panel can be used on a 22kA system. But that series listing option will NOT apply to any Classified Breakers in that panel, again because that series listing option is a tested listing, paid for by the panel mfr. So if your AFC is say, 14kA, you will end up degrading that series listed panel to 10kAIC and you can't connect (legally).