The latest update of the Tor Browser, v9.5, introduced a new opt-in feature that allows desktop users to automatically select the .onion version of a website if that website has one available.
Website publishers now can advertise their onion service to Tor users by adding an HTTP header. When visiting a website that has both an .onion address and Onion Location enabled via Tor Browser, users will be prompted about the onion service version of the site and will be asked to opt-in to upgrade to the onion service on their first use.
The feature can also be turned on or off in the Privacy & Security tab of the browser’s settings page.
To learn more about these new features and everything that’s new in Tor 9.5 check out the official announcement page.