Here is the 'Anchor.js' being injected into the page. There is nothing malicious in the code. I can't comment on why this is injected in the first place.
Thanks for the suggestions. Actually someone else has published the extension on my behalf. I will ask him to add the image at the time of a major release.
The extension runs with background permissions so you don't need to start chrome for using it. It starts automatically at user-login to OS. The projects is open sourced under MIT license.