[Freeswitch-dev] Usage of some core channel functions

Hi all, While trying to add some features to mod_conference I found two functions for access channel data: * switch_channel_get_variable(channel, "conference_controls"); This one is clear, but also * switch_channel_get_private(channel, "_conference_autocall_list_"); Can somebody clarify to me (and maybe to others) what is the purpose of this mechanism? What kind of channel data are generally manipulated this way? Are there useable/settable from application level (dialplan or scripts)? Regards, Mariusz