File Format Significance - Draft Section
Fragment of a discussion from Library talk:Circle/File Format Guidelines
I added this which I think clarifies what I was after:
The following guide lists Preferred Formats (formats that support access and preservation) and Acceptable Formats (formats we accept but convert on your behalf for preservation and access). Please see Section 3.4 of the cIRcle Non-Exclusive Distribution License (Version 3.0) for more details.