Sorry about that, I often blurp out stuff without unpacking the concepts I have in my mind.

On github you can post comments on pull requstes directly inside the diff viewer so that the comments will show up on that line and not as a lonley posts in the feed of the PR.

here is a screenshot:

Without that feature it can be really cumbersome to explain what you don't like or understand in a change. You could reference the lines in your text but that is also hard to parse for the person getting the review.

We also wanted such a system for TALEnet and our triage lead us to a nearly empty solution space. Gogs doesn't want to implement it, gitlab wasn't available in a recent version for sandstorm (which we were using already for other meta coordination) so we went with a standalone gerrit instance wich is working great so far. Also because one of our team members is really familiar with it.