It works by detecting the HTTP Referer header. Under certain circumstances of privacy, Firefox strips the header. For example: https://blog.mozilla.org/security

It works by detecting the HTTP Referer header. Under certain circumstances of privacy, Firefox strips the header. For example: https://blog.mozilla.org/security/2018/01/31/preventing-data-leaks-by-stripping-path-information-in-http-referrers/ https://blog.mozilla.org/security/2018/01/31/preventing-data... It is plainly obvious why Google's browser might not want to do something like that.