freeswitch/conf/vanilla/autoload_configs/abstraction.conf.xml

<configuration name="abstraction.conf" description="Abstraction">
<apis>
	<api name="user_name" description="Return Name for extension" syntax="&lt;exten&gt;" parse="(.*)" destination="user_data" argument="$1@default var effective_caller_id_name"/>
</apis>
</configuration>