There is no documentation page for the SecurityCapabilities class. References to it on pages such as Instance are unclickable.
As this class is used for ReflectionService and a few more things, its highly inconvenient that theres no information about it on the documentation. (I also suspect that there is a bug with the .fromCurrent() constructor, but as there is no documentation, I cannot be sure whether if it is actually a bug or just strange intended behaviour)
Page URL: https://create.roblox.com/docs/reference/engine/classes/Instance#Capabilities