As of https://phabricator.wikimedia.org/rECHU59f3a1f257384b0370cac4f770403eaa12ce7eea in Mar, or time of merge, this requires MediaWiki >=1.41.0. I tried to edit, but this is pulled automatically by a template and i don't want to dig deeper at the moment.
Additionally the repository is not tagged with the version information as suggested by documentation on the page.
Please: update the requirements pulled into the infobox, and/or push tags to the repo with latest compatible version, e.g. compatible-mw-1.35