Template:4

Unexpected use of template  - see Template:4 for details.

The Template:4 is currently a warning to its users. The use of Template:4 is often a common typo where a person intended to access template parameter 4 as (with triple braces) but, instead put only double-braces and invoked "" as Template:4, unaware of the mistake.

However, the most problems have been caused by omitting the first brace "{" of a parameter and getting "}", as invoking Template:4 +"}" rather than parameter 4. This can be an insideous problem, especially when the transclusion of Template:4 is hidden, so that the effect is invisible to the person editing a page. For that reason, Template:4 now issues a warning to the user:
 * Unexpected use of template  - see Template:4 for details.

With that warning, the prior invisible access to Template:4 can now be understood to be a formerly unseen problem coded within a page.

Periodically, people check what-links-here to see if anyone has accidentally invoked Template:4 when trying to use parameter 4, but used only double-braces, instead of triple-braces.