From Fedora Project Wiki
This meta template returns a state of error (recognized as such by a wiki parser function), and optionally an error-message text in red (visible for the user). It is used by other templates to signal an error, for example invalid input, which can then either be displayed to the editor or caught and handled by other templates.
Usage
{{error|An exemplary error}} → An exemplary error
In parser function:
{{#iferror:{{error|Foo}} | Error | No error }} → Error