Manual:$wgHtml5/pl

This setting was not removed in MW 1.22+ but starting with this branch setting it to "false" has no longer any impact.

Szczegóły
Whether to output an HTML5 doctype. Zobacz, aby uzyskać więcej informacji.

If  is set to "true", the markup will be constructed so it can still be processed as XML.

In order to allow the use of microdata attributes in wikitext, set  to "true".