The WikibaseQualityConstraints extension allows defining constraints on Wikibase Properties and checks that the constraints are met when the Properties are used in Statements on Entities. The checks are strictly informational: the extension does not ensure that the constraints are met, it merely informs editors when they are being violated. For more information, see the Property constraints portal on Wikidata.
WikibaseQualityConstraints
extensions/
cd extensions/ git clone https://gerrit.wikimedia.org/r/mediawiki/extensions/WikibaseQualityConstraints
composer install --no-dev
wfLoadExtension ( 'WikibaseQualityConstraints' );
See the "config" section in the extension.json file.