Comment by Tenzer

I think most browsers don't include referrer information when clicking a link on a HTTPS site which leads to a HTTP site, but other than that I believe the information is kept by default.

Site owners can however tell browsers how much information they should include in the "referer" header via the "Referrer-Policy" response header: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Re....