Richard Eisenberg writes:

Hi devs,

I've frequently wanted to attach a summary note to a review, unattached to any line of code. I thought this was impossible, but I see how to do it now.

After making your review, with perhaps many line comments, go back to the Overview pane. Then, you can write a comment at the bottom, and, critically, add it to the review. Then, when you submit the review, the summary comment goes with it.

For what it's worth, this is a somewhat new feature that was added, at least in part, in response to our feedback. We owe some thanks to our friends at GitLab for their responsiveness. Cheers, - Ben