I just stumbled across this and thought it'd be worth formalizing the answer that has already been given in comments by Daniel Fischer and Jyrki Lahtonen. What happened is that the edit was proposed by an anonymous user, i.e. someone who was not logged in. Anonymous edits like that go into a queue to be reviewed by established users with 2000 reputation or higher, and if two out of three people vote to approve it, the edit gets applied to the post. Since there is no user account to associate the edit with, it shows up as having been made by the Community user account. (This particular edit should not have been approved, but that's the reviewers' fault.)
The "Community ♦" account doesn't actually represent a person. It's the public face of an automatic process that does various things on the site. From its profile:
Hi, I'm not really a person.
I'm a background process that helps keep this site clean!
I do things like
- Randomly poke old unanswered questions every hour so they get some attention
- Own community questions and answers so nobody gets unnecessary reputation from them
- Own downvotes on spam/evil posts that get permanently deleted
- Own suggested edits from anonymous users
- Remove abandoned questions
It's marked as a moderator because the process does several things that normal users don't have permission to do.
So any time you see something happen on the site associated with "Community ♦", remember that you have to do a bit more investigating to figure out who (if anyone) actually took that action.
Side note: the naming can be a bit confusing because "community moderator" actually refers to a team of roughly a dozen Stack Exchange employees who are responsible for the Q&A sites at the highest level. In some sense they are the site moderators' supervisors, among other roles. At least some (maybe all) of them have accounts on this site, although they may not participate very much.