This is the ".form/skos:mappingRelation" template. It should be called in the following format:

{{.form/skos:mappingRelation
|hostForm=full pagename of host form
|skosName =eg mappingRelation
|propName =eg skos:mappingRelation
|propLabel=eg has mapping relation
|placeholder=
|text=
}}

Edit the page to see the template text.