Which means nothing, it's not a regulated term, or even a generally specific term. "Quick Charge 2.0" for instance is a Qualcomm technology, and something the 6P doesn't support anyway, but that gives you direct info on the capabilities which are 5V/2.4A, 9V/1.5A, 12V/1.2A.
The Amazon page and the ZeroLemon page for the case lists Input but notably not Output amperage specifications.
It also obviously depends what wall plug you have it attached to. If the wall plug only outputs 1.5A then that's the maximum the device will get.