The layout of your page is really making it hard to read. I feel like the words are trailing off the side of the bounding box.
Also I have to scroll all the way right to reach the end of the sentence. I'm sure the information you posted is useful, but I couldn't spend more than 30 seconds on the page.
My biggest issue with code navigation on Github is that there doesn't seem to be a way to traverse the file tree without navigating through each directory.
It makes getting an overall sense of the organization of the project a bit of a hurdle until you actually clone the repo and look through it (which is too much work if I'm just glancing at something quickly).
For both new-to-project and new-to-programming folks, I'd argue this is very important as it's a scaffolding mechanism for learning the new system.
Have created something similar enabling cross referenced search both from code and diffs as well at https://tixef.com. Indeed the ability to slice into the details of an implementation can be quite useful for actually understanding the code.
Good job making it a browser extension! The low impact install can build on the individual's desires for a better experience.
We use GitHub Enterprise for our git hosting, code review, and issue tracking, but OpenGrok[1] for code perusal. It's indispensable, though this looks like it could be a useful intermediary.
I've noticed that when I click a line number, it correctly highlights the line and updates the URL as usual, but it also scrolls the code view to the top, which is probably not desired.
Off-topic: With today's changes to Github I can no longer see a commit diff by clicking on the corresponding SHA in the commits page. Any idea where has that gone?