Parameters and/or attributes for progress bars & spinners

I found in Adobe XD Change log (XD Release 21.0.12 (July 2019)) that there are new UI controls supported: "Progress bars & spinners – <progress>". However I cannot find anything in the documentation on the subject.
What attributes can be applied on element? Is they a way to actually display a task progress i.e. in percentage?
What element and attributes can be used for a spinner?

Yes, with the adoption of UXP, XD plugins can now use Spectrum components:

This includes the <sp-progressbar> element:

All of the attributes are listed here:

Ah, perfect!
Thank you very much!