Sea is a set of function libraries designed to make the process of writing new World of Warcraft UI mods faster and simpler. It is designed to reflect a Java-like object oriented library style. This addon is a function library. This means that it doesn't have any UI on its own, but rather provides functionality for other addons. If you are an addon user and not an addon developer all you need to do is to leave this addon turned on if you have any other addons that depend on it.
The most current version is available at http://www.wowinterface.com/downloads/info4327-Sea.html.
If you wish to contribute improvements, please comment on the addon page.