query: select ?labelen ?constrainttype ?constrainttypeLabel ?constrainttypeDescription {
    ?constrainttype wdt:P279* wd:Q21502402 .
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
    optional { ?constrainttype rdfs:label ?labelen filter(lang(?labelen) = "en") . }
  } order by ?labelen