(...)
$this->getOutput()
->setPageTitle( wfMsg( 'abusefilter-examine' ) )
->addWikiMsg( 'abusefilter-examine-intro' );
vs
$out = $this->getOutput();
$out->setPageTitle( wfMsg( 'abusefilter-examine' ) );
$out->addWikiMsg( 'abusefilter-examine-intro' );
And if $out was indeed null, just the line number would point out which
object was, instead of needing to test the whole chain.