Execute
composer require mediawiki/container-filter ~1
within MediaWiki root or add mediawiki/container-filter to the
composer.json file of your project
Add
wfLoadExtension( 'ContainerFilter' );
to your LocalSettings.php or the appropriate settings.d/ file.
Within the page content use e.g.
<containerfilter selector=".wikitable tr:not(:has(th))"/>
To filter the content of the container with the given selector. In this case all rows of the table that do not contain a header cell are filtered.