If you are using <h:outputStylesheet> or <h:outputScript>, the referenced stylesheets/scripts can use the EL resource syntax. Developers may need to do this to make references to other resources in their stylesheets or scripts.
For example, if your resource library has a stylesheet that defines a background image, you can't refer to it by URL, since it's part of a resource library, and the image is also a resource. So you use a resource reference in the CSS:
background: #fff url(#
The JSF runtime will substitute the resource reference with the actual location in the application. E.g.:
background: #fff url(/dukes-shipment/javax.faces.resource/background.jpg.xhtml?ln=img)
Why background.jpg.xhtml? It's the extension specified by the JSF servlet in web.xml.
This section should be updated:
See section 2.6.1 of the JSF 2 spec for the resource reference syntax.