The principles document should be independent of metadata formats and publication formats. Following this principle we have removed mention of EPUB and EPUB accessibility conformance hyperlink in definitions, but the introduction still has mention of EPUB. For example:

"Metadata found either inside an EPUB or in its corresponding ONIX file may have important accessibility information that will help end users find and determine if this EPUB can meet their specific accessibility needs."

it can be modified to:
Metadata found either inside a digital publication or in its corresponding ONIX file may have important accessibility information that will help end users find and determine if this publication can meet their specific accessibility needs.