One of the recently updated plugins is Sitenotes. It is now available with its own WSYWIG (what you see is what you get) editor.
As you probably remember, this simple function gives Omeka site administrators (super and admin level users) a place to leave instructions, style sheets, interpretations of Dublin Core fields, or any other notes for the back-end users. Once activated, the new tab appears on the top navigation bar of the admin panel that is accessible to all back-end users regardless of their permission levels.