First launch does a request to facebook.com

[_yet_another_ac]

When I first start firefox, on the welcome page, before I even get a change to open the "Privacy Notice" page in the second tab, there is a request (among a zillion more for telemetry and other garbage) to facebook.com.

I thought Firefox was the one browser that doesn't do shady stuff like that.

[lackey]

How did you catch this request? Do you know whether it's from one of the default webpages the browser opens, or from the browser's internals?