The Atlassian Gadgets framework allows you to specify #-directives in your gadget specification XML file that will be replaced by generated content at run time. These #-directives are provided by the Atlassian Gadget Publisher plugin. They work for any gadget that is provided as a plugin in an Atlassian application. The #-directives do not work for gadgets that are served from an external web server.
(info) #-directives are sometimes also called 'macros' or 'pseudo-macros'.