Google Music Media Keys is a free Chrome extension developed by Jean-Lou Dupont (systemical). It falls under the category of Browsers and is classified as an Add-ons & Tools subcategory.

This extension allows users to control Google Music using media keys. With Google Music Media Keys, users can use their keyboard's media keys to play/pause, skip to the previous or next track, as well as configure two additional keys for the "thumb up" and "thumb down" buttons.

One of the main advantages of this extension is that it eliminates the need to switch between browser tabs to control Google Music. Users can access the keyboard keys configuration through the menu (More Tools -> Extensions -> Keyboard Shortcuts) and easily customize their media key settings.

To activate the extension, simply press the "play/pause" button on the Google Music UI. This feature is especially useful when multiple Google Music tabs are open, as it helps the extension determine which tab to focus on.

In the latest version 0.0.2, improvements have been made to the play/pause status discovery when multiple Google Music tabs are present.

Overall, Google Music Media Keys is a handy Chrome extension that enhances the user experience by providing convenient control over Google Music using media keys.