This template adds page to Category:Wikijunior Stubs. With no parameters, it produces the message

This Wikijunior article is a stub. You can help Wikijunior by expanding it.

Optional parameter {{{topic}}} describes what sort of page it is. For example,

{{Wikijunior article stub|topic=a famous [[w:inventor|inventor]]}}

would produce the message

This Wikijunior article about a famous inventor is a stub. You can help Wikijunior by expanding it.