Even after explaining it to the company, we get new people starting to use Phabricator, or we have people who don't use it often and forget, and the result is that we often need to remind people what "Test plan' means and what to put in there (typically people put nothing or write how to test, not how they actually tested the change).
It would be very helpful if there were some inline tooltips in both arcanist and the Differential app with concrete explanations of what to put in title, summary and test plan.