Portlet labels and description are being translated on different translation levels

First and foremost, it doesn't seem, that we need to define schemes for homebox portlet types. E.g. "block_content" and other core modules do not define a schema when they define a new block.

I think the (Empty) mapping bug comes from the way we save the homebox portlet types in our homebox type.
Currently, any HomeboxType has an array called "$homeboxTypePortletTypesSettings", which saves the homebox portlet type as key and the values are "label", "description" and a bunch of boolean values (e.g. "status"):

This perfectly translates to the translation UI. We are not actually translating the portlet types, but the homeboxTypePortletTypesSettings array instead (since the homeboxType doesn't know about the portlet plugins). That's why we also only get to translate "label" and "description", since these are the only translatable values inside the array:

And both label and description are not set, until they are overwritten, that's why it says "empty" for the original label and description values.

If the fields for label and description of the portlet types are empty, it's correct to show them empty in the config translation (no bug)
Typically it would be great if the details in the form would show the programmatic label, but that would require custom coding and I guess it's not worth it.

So this isn't a bug and the feature requests solution would simply be too expensive. So let's keep it like this. Not nice but working correctly!