Order matters in \usepackage{hyperref}.

The problem exhibited only in PDF files, wherein \ref{} links to
appendix chapters referred instead to regular chapters.

http://tex.stackexchange.com/questions/77886/fncychap-and-hyperref-messes-up-page-references
suggest that loading hyperref second fixes the problem.  This indeed
worked.
Contributing text from third-party works.

Integration of text from third-party works is complicated, since the
text must be incorporated to flow properly with the rest of the Guide.
Also, historical archiving commits are particularly useful in such
situations.  This tutorial explains how to contribute such additions for
this project.