Wikimedia Bugzilla is closed!

1.4 beta 5 bug:

$t = preg_replace( '/[\\s_]+/', '_', $this->mDbkeyform );
$t = trim( $t, '_' );

if we use utf8 in mediawiki, some urls corrupts and wiki shows the page about "incorrect title". For example, 
russian letter "P" in utf8 looks like \xD0\xA0. This code replaces А0 with underscore and deletes it, so we 
have corrupted utf8 string.

1.3.9 works well
$t = preg_replace( "/[ _]+/", "_", $this->mDbkeyform );
$t = preg_replace( '/^_*(.*?)_*$/', '$1', $t );