"bury in the appendix" means?

In this case, "appendix" likely refers to a section at the end of a book containing supplementary information.

See http://www.wisegeek.org/in-a-book-what-is-an-appendix.htm

This is what you would do if you submitted a thesis or something, the appendix is normally where you put things like examples of questionnaires. You bury it in there when you have to include it but don't really want people to look at it too closely

Appendix may refer to:

In documents:
Addendum, any addition to a document, such as a book or legal contract
Bibliography, a systematic list of books and other works
Index (publishing), a list of words or phrases with pointers to where related material can be found in a document
Specifically, a text added to the end of a book or an article, containing information that is important to, but is not the main idea of the main text