profile\actions\edit.php - Modify Profile

Dear All,

I am going through profile\actions\edit.php code and got confused bit since there is no update_metadata method used . Instead remove_metadata and create_metadata used . Can't I update using update_metadata method?

Could somebody throw some light on this ?

and also there is call to trigger_elgg_event('profileupdate',$user->type,$user); Can I what does this do? or any doc


Thanks for your help