[undertow-dev] Custom authentication mechanism

Hi. I need to develop my own auhentication mechanism. I have found few information about how to do it at http://undertow.io/undertow -docs/undertow-docs-1.2.0/index.html. The paragraph "Servlet Extensions" indicates that more examples can be found in the deployement guide. But the given link to the webpage http://undertow.io/und ertow-docs/undertow-docs-1.2.0/deployment.html is dead. Same thing for version 1.3.0. Is the deployement guide available from another location ? Regards.