You can place static include files or executables in the ssi folder. The static files will be place right after the body or just before the end of the body.
|This has nothing to do with the Apache module 'mod_include' and just implements the nagios way of SSIs.|
There are global includes, which will be included in every cgi page:
And there are page specific includes, which will only be placed in the specific page:
Replace <page> with the name of the page. You can find the page name in the url (see screenshot). Includes are only possible for the cgi pages, not for static html pages like the index.html.
Files will be statically placed inside the output of the normal cgi output. Executables will be executed and the output will then be used as content.