Apparently this is now an option provided by Eugens mastodon software: enabling http_referrer on outlinks.
Just as an FYI, this setting will only enable the data surveillance corporates to build yet more granular detail on who you are and what your preferences and beliefs are.
If you're an admin on a server that hosts other people, I think it behoves you to make inquiry of those users before enabling such a privacy violating option.
