Property:Allows value
From AcaWiki
"Allows value" is a predefined property that can define a list of permissible values to restrict value assignments for a property and is provided by Semantic MediaWiki. This property is pre-deployed (also known as special property) and comes with additional administrative privileges but can be used just like any other user-defined property.
Allows value is a [1] in Semantic MediaWiki with a built-in meaning: it lists one permissible value for a property.
You can use this special property with a property of any datatype to limit its possible values. For example, the page for a Problem severity property might contain:
[[allows value::Enhancement]],[[allows value::Trivial]],[[allows value::Minor]], [[allows value::Normal]],[[allows value::Major]],[[allows value::Critical]]
See http://semantic-mediawiki.org/wiki/Property:Allows_value