We noticed recently we had a PR that only had a few lines added and no coverage on these yet the Quality Gate still passed. Before raising this I search for the issue and found this thread that says a banner is displayed explaining it and hovering on the question mark tells you you need 20 lines before coverage is applied.
I’m fine knowing that now but the banner shown here from that post doesn’t appear to be showing anymore or at least not when I navigate to the Pull Request.