Knowledge is broken down by ease of discovery/availability; Any attempt to know more than what's Pervasive will require a reference, source, knowledge, check, or access to someone who can get or provide either of these.
Warning Obscure/Hidden Knowledge is not generally available in known references; It is not necessarily Forbidden. DO NOT READ BEYOND THIS POINT unless a character has the capability to gain such knowledge [through association, organization, or relation] if they do not possess it themselves or the reader intends to participate in scenarios using this material as a PLAYER! GM Narration will typically provide relevant information by check or story.