On November 08, 2013, Google introduced the Chrome Apps & Extensions Developer Tool app, which helps developers build and debug Chrome apps and extensions. A little over seven (7) months later, June 10, 2014, Google has released an updated version of the Chrome Apps & Extensions Developer Tool app, which allows for auditing of any app or extension, so you clearly see the precise actions the app or extension is performing.What is great about this app is that you can see what the app or extension is doing, which is important because some apps and extensions request broad permissions to sensitive data such as browser cookies or history.
To install the app, go to the Chrome Web Store. Once installed, open the app and you’ll see to tabs in the menu; one tab for apps and the other tab for extensions. Click on the tab you want. Search for the app or extension you want to see the behaviour for. Then click on the “Behavior” link, which is located at the bottom of each app or extension.
Source: Google Online Security Blog