This is interesting. No sooner did I post the message containing the URL when something/someone attempted to retrieve it. I mean, within *seconds* of the posting. And they attempted to retrieve the example address, which is clearly fake. So I'm going to list another URL https://gw.ampr.org/private/no-such-file.txt and see if it's an automated process that tries to fetch them.
Please excuse this bogus email. - Brian