How did Google, Comscore and Grapeshot learn of a secret page

I have a secret web page, let’s call it something123.php, and looking through my Apache webserver access.log I waas surprised to see that two entities have learned of this page.

  1. Google
  2. Grapeshot.co.uk
  3. Comscore

I have the page in my bookmarks, but I noticed something especially odd.

In one case, 20 seconds after I accessed the secret page, Google did too.

In another case, 4 seconds after I accessed it, Comscore did too and then 5 minutes later, Grapeshot did.

I am curious to learn how this could be. I use Firefox, and my extensions consist of only one: UBlock Origin. I have a theme installed from Mozilla for dark mode. That’s it.

I may have been running Ungoogled Chromium at the same time as Firefox but I would think it wouldn’t leak information.

It feels like I have spyware on my computer.