WordPress at a glance
action is not described

admin_post_(action) action-hook . WP 2.6.0

Fires on an authenticated admin post request for the given action.

The dynamic portion of the hook name, $action, refers to the given request action.

Usage

add_action( 'admin_post_(action)', 'action_function_name_9433' );
function action_function_name_9433(){
	// action...
}

Where the hook is called

In file: /wp-admin/admin-post.php
admin_post_(action)
wp-admin/admin-post.php 69
do_action( "admin_post_{$action}" );

Where the hook is used (in WP core)

Does not used.