Why do you ask for permission to read, write and change the data on visited sites? This extension only resizes the window.
The extension doesn't actually reads, writes or changes any of your data, but it needs that permission because:
I hope my answer makes it clear why you see that message.
P.S.: I hope you don't mind I change the visibility of this ticket to public, so others that might be wondering the same thing can see my answer.
Thanks for your explanation, makes all a lot more transparent to me. As I also write a collection for Chrome OS on Google+ I'm able to recommend your extension to others.
Customer support service by UserEcho