Previous commenter said they tried and it worked with Firefox.
I'm hoping they add "hide my email" to third party browsers too, really inconvenient having to swap back to Safari or use a workaround every time I need to enter an email address.
The article says from Apples Messages which was previously limited to just Safari. This isn't about expanding email auto fill from Apple Mail to third party email clients.
I have 2 macbooks and both are upgraded to Tahoe. One macbook stopped showing this SMS verification code suggests after some time, one still works. I'm not sure what settings I've disable that prevented it from working. It still receives SMS forwarded from my iPhone but it's just not showing the Fill code xxxxxx popup in Chrome/Firefox, etc, but still works in Safari.