Code review comment for lp:~michael-sheldon/webbrowser-app/general-download-support

315 + headers["Referer"] = request.referrer

It seems "referer" is a common mispelling of "referrer", would that be a bug/typo in UDM?

317 + headers["User-Agent"] = webview.context.userAgent

This won’t get us the overridden UA if any, it’s probably good enough in most cases but I would bet some corner cases will fail because the download is not requested with the same UA as the one that was used to request the parent page.