A quick way to test this bug and play with it is with this in LocalSettings.php

$smwgNamespacesWithSemanticLinks = array(
NS_MAIN => true,
NS_TALK => false,
NS_USER => true,
NS_USER_TALK => false,
NS_PROJECT => true,
NS_PROJECT_TALK => false,
NS_MEDIAWIKI => true,
NS_MEDIAWIKI_TALK => false,
NS_TEMPLATE => true,
NS_TEMPLATE_TALK => false,
NS_HELP => true,
NS_HELP_TALK => false,
NS_CATEGORY => true,
NS_CATEGORY_TALK => false,
SMW_NS_PROPERTY => true,
SMW_NS_PROPERTY_TALK => false,
SMW_NS_TYPE => true,
SMW_NS_TYPE_TALK => false,
SMW_NS_CONCEPT => true,
SMW_NS_CONCEPT_TALK => false,
SF_NS_FORM => true,
SF_NS_FORM_TALK => false,
);

And then use this on a wiki page to display one of the newly added namespaces ("Mediawiki" in this example):

{{#ask: [[:Mediawiki:+]] | ?Modification date | mainlabel=Mediawiki namespace [[Special:AllPages]] | limit=500}}

This makes sense since this data gets saved on save, so it won't magically
appear on all pages when enabling it. If you want it to show up everywhere
immediately, then you can run the data update/refresh thing on SMWAdmin and
then run maintenance/runJobs.php. If you can't do the later, at least the data
will be set eventually (depending on your wikis size and jobQueue settings)
without having to do more manual work.