In Chrome 59, extensions could not fetch ftp resources any more due to issue 435547 .

Just now, it has been decided that ftp support is not going to be removed from Chrome after all - issue 333943 .

So it seems reasonable to lift the restrictions from issue 435547, i.e. to allow extensions to fetch ftp resources.

Use case: https://github.com/mozilla/pdf.js/issues/8926