after this line:
$file = DIR_WS_LANGUAGES . $language . '/' . $file_name;
add this:
$newfile = 'whatever you want...';
change:
'title' => sprintf( MODULE_CONTENT_HEADER_STORE_SEARCH_PAGE, substr(basename($file), 0, -4)),
to:
'title' => sprintf( MODULE_CONTENT_HEADER_STORE_SEARCH_PAGE, $newfile),