Great idea for sure, but I think the GitHub link should be inside your Chrome Web Store page to reduce the fear of possible malicious intent (not accusing you/your extension or anything, just a suggestion).

I am one of the skeptics out here when it comes to extensions, there have been enough out there with malicious intent. How can I be assured this extension runs solely on the GitHub open-source code and doesn't have any little 'tricky' code lines inside?

Not a developer and never studied how GitHub or extensions really work, so I think this is the best opportunity to learn it. If you plan on creating a website for your extension, I'd add a very short F.A.Q. and have my question included for the skeptics.