// Sanity check the file extension against known cache types
if ( $mts < $this->minSurviveTimestamp
&& preg_match( '/\.(?:html|cache)(?:\.gz)?$/', $file )
// Sanity check the file extension against known cache types
if ( $mts < $this->minSurviveTimestamp
&& preg_match( '/\.(?:html|cache)(?:\.gz)?$/', $file )