From Semantic Web Standards
"Date" is a type and predefined property provided by Semantic MediaWiki to represent date values. 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.
Date dc:date (dc | DCMI Metadata Terms)
Facts about "Date"
"Imported from" is a predefined property that describes a relation to an imported vocabulary and is provided by Semantic MediaWiki.
"Has type" is a predefined property that describes the datatype of a property and is provided by Semantic MediaWiki.