fz_link is a list of interactive links on a page.
There is no relation between the order of the links in the list and the order they appear on the page. The list of links for a given page can be obtained from fz_load_links.
A link is reference counted. Dropping a reference to a link is done by calling fz_drop_link.
rect: The hot zone. The area that can be clicked in untransformed coordinates.
uri: Link destinations come in two forms: internal and external. Internal links refer to other pages in the same document. External links are URLs to other documents.
next: A pointer to the next link on the same page.