Australia is considering requiring social media platforms to
check
the age of each user. This article describes the mechanisms that might be used. It seems that
each one will either require you to identify yourself to some other service that could keep track of
everything, or require some sort of unalterable unique number from your computer. I expect they
will demand something that users can't alter, which implies rejection of free operating systems (on
a free operating systems, you could always set it to whatever value you like).
So I think this represents a plan to require that users either identify themselves, or run nonfree
software (which will probably snoop on them), or both.
But I can't be completely sure of that — I have to make guesses about what some of these
things mean.
There is a system that can verify your age to a web site while refusing to identify you to that web
site: GNU Taler can be adapted to let you get tokens that you can use to
prove you are over N years old, but that would not enable the site to identify you, and that won't
allow the Taler site to know which sites you gave them to.
But that is not in the list of what Australia is considering.