Is this what you are looking for?
This is related to this topic.
Can anyone explain me what does this mean?
Rounding out key features of Mendix 9 is a significant update to Atlas, the Mendix UI Framework. Atlas3.0 provides a default design system out of the box that is sleek and modern, for web, native mobile, and PWA. And the Mendix UI Kit equips designers to work in Mendix development teams using their preferred tools including Figma and Sketch.
I would like to understand the use case scenario in which you can use figma or Sketch to speed up the design process in mendix or to at least standardize the controls/widgets/patterns. Do you have documentation about this?
Thanks in advance.