The Print module, Book module's export functionality, the s5 module, they all have this trick of taking over the entire page output for their own theme function.
I am building a module that is headed toward a more generic mechanism for funneling content through a pluggable template, but despite pouring over the code I can't see the magical place where all other Drupal markup is dropped in favor of the HTML document described in my own template file. What's the trick? I have a menu callback along the lines of "present/%node" and it leads to an export function that returns my theme function, which is a template outputting a complete HTML document.
