This is a follow-up to Edit marked as by "Community User" I've noticed that some "Community" edits are not associated with any revision. For example, here's a question that is reported to have been modified by "Community":
However, if I click on it, I don't see any revision history.
What did "Community" do, in this instance? Is it some automated task that the system runs to bump unanswered questions to the top?