When a "duplicate" close vote or flag is cast, a box appears above the question visible to the question's owner. It prompts the author to either edit the question to clarify its non-duplicateness or accept the duplicity by pressing a "yes, that solved my problem" button. If the user chooses that button, the Community user casts the final duplicate vote, ...
It shows that "Community User" has reviewed and approved the edit I proposed.
When a reviewer (2k+) improves a suggested edit then it is marked as reviewed and approved by community.
In your example Ben N chose "Improve Edit" during the review.
Why Community in this case?
This is by design. I wanted a simple way to track all the edits that are approved ...
One of the privileges you receive at 2000 rep is the ability to edit other users posts without any approval stage. Any user with 2000+ rep can amend any other users post immediately.
Should this occur, the system still expects an approval step, which in this instance will be performed by the user @Community.
For more information, see here