@Override
        public String getName() {
            return "skip-if-unavailable";
        }
A comma-separated list of the identifiers of all authentication
providers whose internal failures should be tolerated during the
authentication process. If an authentication provider within this list
encounters an internal error during the authentication process, it will
simply be skipped, allowing other authentication providers to continue
trying to authenticate the user. Internal errors within authentication
providers that are not within this list will halt the authentication
process entirely.
guacamole/src/main/java/org/apache/guacamole/extension/ExtensionModule.java