From the Introduction:
Explorer's Report: California Nebula is a special setting companion set in the far fringes of the BattleTech setting, presenting unique new worlds and environs that may be used to spice up your BattleTech campaigns, whether they are role-playing adventures using the rules found in A Time of War (AToW), or the tactical combat rules found in Total Warfare (TW) and Alpha Strike (AS).
Of course, given the fact that we are releasing this puppy on the first of April, a day we tend to reserve for mischief, it should be obvious to all that the material and rules presented in this electronic volume are provided purely in the interests of fun, and may be considered non-canon. No, really; as much as we would love to claim that what you find inside this book is really happening in the BattleTech universe, it's really not.
[Author's Note: Well, actually, it could all be canon; we’re not sure. It seems that something surrounds the California Nebula that allows JumpShips in, but prevents them from leaving its boundaries. These poor IE folks you'll be hearing from? They can jump out any time they want, but they can never leave! It's a real wonder how their reports are even making it into your hands, in fact... Are you a spy or something?]
[Developer's Note: The developers would like to apologize for the author's rant above! Rest assured, that he is clearly delusional, and will be sacked. Nothing to see here! Move along!]
Anyway, canon or no, basic rules covering the use and effectiveness of the technologies, techniques, and equipment for your BattleTech games can be found at the back of this volume. As unconventional as they might be, they may be introduced to games based on the core rules found in TW, TO, AToW, and their various companions. For the benefit of players who concern themselves which such things, the data for all of the featured units and material in this book are the very definition of Experimental-level rules, regardless of their era of play.
[Writer's Note: Even future eras?]
[Developer's Note: Especially future eras! Now, go box your stuff!]
So, you know, read on and have fun!