Hugo , with all due respect can you please clarify the argument?
All browsers can safely "read" Check Point content but Firefox, since they shifted some gear in latest updates I believe this started in version 54 actually.
There are multiple security fixes applied to their new webextention feature, and also around Java script, in Mozilla Forum there are multiple complaints like this after upgrade.
Starting 56 and still in 57, we can't even download tgz files from Check Point Usercenter , just out of nothing, I can no longer login using firefox to sony entertainment network and this example is completely out of scope here, is just to show other example, here firefox complains about cookie problem and nothing but an update has been performed, even in safe mode, and without any extentions/add-ons running.
(Ironic mode on) I guess firefox is the only browser doing things right...because no one else(browser) has issues such as this.
If this was security issue that by complying to your RFC could anyone be protected, all the other browsers would also stop working.
Don't mind me saying, Firefox is my first personal choice to browse, but lately, my confidence in it's ability to deliver as declined significantly.
Saying this, I'm totally against the idea that a single browser option should be even recommended publicly.