It contains usage information, categories, and other content that is not part of the original template page.
Usage
Tnull is used to nullify templates in the monospaced font. It is similar to {{tlx}} in the way that it has support for many parameters, but it does not link the template name. It is similar to {{tlc}}, but does not prevent text wrapping.
Example
Typing {{tnull|foo|bar|baz|boo}} in the edit window would yield {{foo|bar|baz|boo}} in the rendered page.
Special character handling
"=" (equality sign)
If there is a "=" character (equality/equals sign) in any parameter, it must be replaced with = [or {{=}}?]:
{{tnull|click|image=image name|width=width|height=height|link=page name}}
Or you can use parameter-number=value as in:
{{tnull|click|2=image=image name|3=width=width|4=height=height|5=link=page name}}
Either method would yield the following output:
{{click|image=image name|width=width|height=height|link=page name}}
"|" (vertical bar, pipe)
If a second consecutive pipe (|) is used to denote that a parameter has been skipped, you must replace it with | as in:
{{tnull|look from|Alan||all the Alans}}
That would yield the following displayed output:
{{look from|Alan||all the Alans}}