When a comment in Maniphest is edited, it'll display "Edited" afterwards for the sake of transparency.
But this is not the case after having edited the initial description comment. The only way to find out is hidden somewhere down the page in a "Foo edited the task description." line.
Current behavior feels slightly inconsistent; would expected an "Edited" near "Description".
Brought up in https://phabricator.wikimedia.org/T194
(Here's a trivial edit.)