$wgFileExtensions = array_values( array_diff( $wgFileExtensions, $wgFileBlacklist ) );
if ( $wgInvalidateCacheOnLocalSettingsChange ) {
$wgFileExtensions = array_values( array_diff( $wgFileExtensions, $wgFileBlacklist ) );
if ( $wgInvalidateCacheOnLocalSettingsChange ) {