Editing Template:Categorytemplate/doc

<code><nowiki>{{Categorytemplate|type=module}}</nowiki></code>

prints:

{{Categorytemplate|type=module}}

With <code><nowiki>1=</nowiki></code> prefix, and the text you want to print out, it will print big text in blue.

<code><nowiki>{{Categorytemplate|1=Templates relating to something}}</nowiki></code>

{{Categorytemplate|1=Templates relating to something}}

The <code><nowiki>2=</nowiki></code> prefix does the same thing but next to the "The pages listed.." text. This can be used for small bits of extra info. See any use of this template for an example, including the source code for it to check.
<noinclude>[[Category:Template documentation pages]]</noinclude>