Template:Documentation
This template automatically displays a documentation box like you are seeing now, of which the content is transcluded from another page. It is intended for pages which are transcluded in other pages, e.g. templates, whether in the template namespace or not.
Usage
Normal /doc
<noinclude>{{Documentation}}</noinclude>
Any /doc page
<noinclude>{{Documentation|Template:any page/doc}}</noinclude>
In-line content
<noinclude>{{Documentation|content=This is documentation.}}</noinclude>
In-line content with [view][edit] links
<noinclude>{{Documentation
|1 = Template:any page/doc
|content ={{Template:any page/doc|parameters}}
}}</noinclude>
Best practice
This code should be added at the bottom of the template code, with no extra space before "<noinclude>" (which would cause extra space on pages where the template is used). The parameter can be used as shown above to transclude an arbitrary documentation page.
Add categories and interwiki links to the documentation page inside <includeonly> </includeonly> tags.
If the documentation page contains includeonly or noinclude tags as part of the documentation, replace the "<" with "<".
Customizing display
Overrides exist to customize the output in special cases:
{{documentation| '''heading''' = ...}}− change the text of the "documentation" heading. If this is set to blank, the entire heading line (including the first [edit] link) will also disappear.
Functions
If the documentation page doesn't exist, the "edit" link includes a preload parameter so that clicking it will pre-fill the edit form with the basic documentation page format.
Rationale
Use of this template allows templates to be protected where necessary, while allowing anyone to edit the documentation, categories, and interwiki links.