The default download path is always the standard download location (QStandardPaths::DownloadLocation) and this cannot be changed before we get the notification from QWebEngineProfile::downloadRequested() signal. The download path can be changed by QWebEngineDownloadItem::setPath() but the existence of the file has already been checked at the standard default location. 

Because of this the file indexing (in case of existing file) works with default download path only.