"Has type" is a predefined property that describes the datatype of 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.
Has type is a special property in Semantic MediaWiki with a built-in meaning: it assigns a type to a property. Special:Types lists the types available in the wiki. See datatypes in the SMW Help system.