"Query string" is a predefined property that describes the conditions of the query as a string 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.
[[:-3Cspan class="smw-highlighter" data-type="4" data-state="inline" data-title="Warning" title="Some use of "" in your query was not closed by a matching ""."><span class="smwtticon warning"></span><span class="smwttcontent">Some use of "]]