[kazinator]

> opt into the new scheme

Checkbox:

  Append common required chars [ ]: @Zz1

The roll out is that this is unchecked by default initially with a warning that the default will be checked. Then eventually it defaults to checked.

[stepchowfun]

Yes, a checkbox is one way to allow users engage with this feature. There are other changes I'm considering as well (e.g., increasing the length of the generated passwords, avoiding characters that look like other characters such as 0 and O, etc.). You have the right idea, but the new experience needs to be designed holistically.