The default attributes prop (mandatory and managed by Drupal) was not covered by UI Patterns Settings and not showing up in UI Patterns 1.x forms.
The new UI Patterns architecture (prop type + source plugins) allow us to expose it easily. But it is not the case yet and it is visible in Form Builder only when the prop is explicitly present in the definition file (which is not a good practice).
We don't want it to show up elsewhere (library pages...) and we don't want to force the front developer to add attributes prop on every component definition.
So, do we add this prop to the form in the form builder?
Active
2.0
Code
We don't do it automatically because some (most?) projects doesn't want the attributes to be exposed for every components.
It is better to do case by case, by adding attributes in the props.
However, if a project wants this attributes and:
we need to provide a hook in the definitionsAlter of the compoennt plugin manager