The concept of a stability index where the likelihood for the content, where it is code or a specification (e.g. in the documentation of the Node.js API) looks to be rather useful and can be adopted for use in the UI/Visual design style guide.
Since the UI is generally an evolving aspect of the software, some aspects will inevitably change, with other aspect becoming more persistent and stable than others. Where there is a high likelihood of change or instability, it is practical to document so that designers and developers can be made aware.
Is this a useful concept to include when documentation UI design components and patterns in a print or digital style guide? Has anyone seen the implementation of this concept anywhere?