Moar accordion makes your tray icons spread in an accordion effect way to show more info about the icon you are hovering your mouse over. When hovering over a contact for example, the name of the contact will be displayed next to the icon.
Although things like this should be configurable from tools provided by the environment itself, it is nice to see that people offer extensions of usability like this one. This kind of accordion functionality is something that was removed on 3.6 message tray, but real life shows that many people still need it for obvious reasons.
To install this extension, simply turn the switch to “ON”