Overview

When looking into the Webrequest external referer data for T239625, I found a few unusual referers that are currently classified as referer_class=unknown. I find them abnormal specifically because they do not contain an HTTP(S) method.

The two primary examples:

• google.com: ~42% of unknown referers ('Real' Google Search referers ~ https://www.google.com/)
• en.wikipedia.org: ~1.3% of unknown referers ('Real' Internal English Wikipedia referers ~ https://en.wikipedia.org/)

Resolution

I expect that these should remain classified as unknown, as I don't believe that they are from the sites from which they appear to be. That said, a more in-depth look into them may reveal that we should classify them as external or internal.

@Nuria suggested that they may be the result of bots/scripting. I believe that this is the most plausible explanation.