It seems to be a plugin that is dedicated to UI changes for WordPress 3.6.
Simplifying the wp-admin UI is a challenging task, as flattening the icons showed us when you improve one thing it just makes all of the other out of date elements stand out more.
Trunk isn’t terribly well-suited for UI iteration, so this plugin is a chance for us to rapidly iterate in a way people can use and test some new ideas for how to visually tie together the aesthetics of our current wp-admin UI.
User Interface Changes
It seems that there are a few noticeable changes with the UI when you activate the plugin. The icons have been changed to more of a flat design.
They are looking for specific feedback about the icons and you can join in here if you like. The other thing that I noticed that has been changed is the meta box header background colors. They too seem to be flat without a gradient background.
It seems that they will be using this plugin as the avenue to iterate through the UI design. If you want to keep up with the changes, then I suggest you install and activate MP6. I’m sure with each plugin update will come some UI changes.
Plugin Name Meaning
The plugin supposedly doesn’t stand for anything. I think it would be fun to make up some ways the plugin got its name. Tom thinks if you just flip the W around you get M in MP. I’m guessing the 6 comes from the next version 3.6.
What story or meaning can you come up with?