Tested on https://www.sondages.pro/iframe/

(please confirm : i like to disable iframe on this demo)

tested on

• Edge 119.0.2151.72 / windows
• Firefox 115.4.0esr (64 bits) / linux (with https://support.mozilla.org/fr/kb/protection-renforcee-contre-pistage-firefox-ordinateur at strict + ublock + privacybadger)
• Version 119.0.6045.123 (Official Build) built on Debian 12.2, running on Debian 12.2 (64-bit)

There are settings where user can not access

• Chrome : incognito mode OR disable third party cookies

Is this a feature/setting that got silently removed?

Manual update, yo still have IFrame embedding allowed: but it don't work ouit of the box you need to ,updfate config.php too (manualy)
for sameSite setting for cookies