This tag is Resources plugin
// actually imports '/app/js/myscript.js'
If you do not include a "library" or "src" attribute but instead provide a body, the result is an inline script.
contextPath (optional) - the context path to use (relative to the application context path). Defaults to "" or path to the plugin for a plugin view or template.
library (optional) - The name of the library to include. Typical values include "jquery", "prototype", "scriptaculous", "yahoo" or "dojo" but plugins can contribute new providers. If the Resources plugin is installed, no link to the library will be rendered immediately. Rather, it will include the resource module with the same name as the library and let Resources do the rest. This means you must have a resource module declared with the same name, as if you had used an
<r:use module="jquery"/> tag.
base (optional) - specifies the full base url to prepend to the library name