Error
MediaWiki version: 1.36.0-wmf.34
Argument 1 passed to Wikimedia\Parsoid\Html2Wt\WikitextSerializer::stripUnnecessaryHeadingNowikis() must be of the type string, null given, called in /srv/mediawiki/php-1.36.0-wmf.34/vendor/wikimedia/parsoid/src/Html2Wt/WikitextSerializer.php on line 1647