Even outside of pull requests, you can (on Github) open a file and add a comment to it. You can reference specific lines via the Github URL in each comment. It

Even outside of pull requests, you can (on Github) open a file and add a comment to it. You can reference specific lines via the Github URL in each comment. It gets a bit murkier if you need to connect comments in one repository with comments in another repository but the workflow is pretty similar... just share the link to the lines you want. Make sure to press `Y` on your keyboard to get a specific commit instead of just `master` because `master` can move the lines around and you'd end up linking to some other code in that case.