Most tutorials propose a default JSF configuration similar to the following web.xml:
javax.faces.DEFAULT_SUFFIX&l
You can use Filter to hide this extension and make your URL SEO friendly. One such implementation of Filter is PrettyFaces.
For example:
If you need http://host:port/yourapp/login to resolve with your login.xhtml then in pretty filter configure following way
/login
/legacy/user/login.jsf
Have a look at two min video tutorial