TVTropes.org Idea

There's an interesting suggestion at tvtropes.org regarding series bibles ...

thus, if it's written in the Universe Bible, it's considered de facto canon, even if it's never mentioned in the series itself.

Not so sure about that. Unless a push is made to both conform to and include facts within the bible (which defeats the purpose of considering the bible canon anyway, given that it just went on screen), then one can readily find the bible contradicted.  Sure, some writer-for-hire won't probably have that ability, but if some superb story comes up that features a rule or fact violation -- some departure from the biblical position -- then chances are good the bible's out and the story's in.   (The same is often true of simple continuity concerns, after all.)

Ostensibly, of course, the bible is precisely what is to be conformed to by everyone, and should be constantly updated and so on. But in practice, that may not be so.

Thus, you can't assume a de facto canon status for the Universe Bible of anything, in my view, without some real proof.  Mere elements of the bible coming to pass are not proof enough; to my mind, you probably should have the explicit blessing of the creator/owner.  Even then, however, the show itself ... the primary depiction to the audience ... must take precedence.

Just a thought.