@test: works fine for me, a good addition.

The space between the required label and the title is bigger in the edit form than the registration form. This is because there is a control-group div with a hidden field above required label at the edit form. Maybe whe can hide this div by adding hidden to the class?

We don't show that text in all other forms from what I see. The only one where it is used is the user registration.

Also the language string used indicates that it's only used in the registration process, not in the profile which uses a different prefix. So to be consistent, you would have to add a new language string I think.

If a template overrides the label JLayout to not include that asterisk (as discussed in the other PR #4139), then you would have a misleading text. It would be quite hard to actually remove that line in a template override because it comes from the form and not the layout itself. In the end you would make overrides harded with this change.

Also given that the asterisk is actually quite common and standard in many forms, I doubt you really need to explain it to the users nowadays. I would actually rather remove it from the registration form, but that's me

Not very user-friendly to add intrusive obvious instructions in important forms. If you want to add text for the image-blinds, just add a title attribute to the span surrounding the star, so people see on hover or tap what it means. And maybe add html5 semantic to the input.

Stars are part of standard UX nowadays. Worldwide. Imho.

We don't show that text in all other forms from what I see. The only one where it is used is the user registration.

The account creation form is the only form that currently includes this, IMO redundant, legend. I'd rather see it removed from this form than added to any others.