These are pretty cool! "Suggested Changes" are in public beta and allow you to pitch code alterations which can be one-click merged.
You can apply a suggested change directly in a pull request if you have write access to the repository and are the author of or assigned to the pull request.
I have not actually made use of this yet. Have you? What is your opinion either way.
Many times as a mobile developer I have to work on apps without the API ready that was crucial for the feature I was implementing. Either the backend was developed by another team that was not entirely in sync with us or our backend team had no chance to implement those endpoints earlier. For this reason, I was not able to satisfy the Definition of Done but it does not mean that I have implemented the UI only.