(Answers developer) This is a new feature in MATLAB Answers which allows you to run your MATLAB code directly from the MATLAB Answers editor. This feature is being progressively rolled out to all users of this forum.
So once you get the access to this feature, a new Run button (similar to Run button in MATLAB) will appear in the editor's toolstrip. That run button will allow you to run your MATLAB code here and post it, like you see in the example image you provided.
