WordPress at a glance
action is not described

add_inline_data action-hook . WP 4.9.8

Fires after outputting the fields for the inline editor for posts and pages.

Usage

add_action( 'add_inline_data', 'action_function_name_7360', 10, 2 );
function action_function_name_7360( $post, $post_type_object ){
	// action...
}
$post(WP_Post)
The current post object.
$post_type_object(WP_Post_Type)
The current post's post type object.

Where the hook is called

get_inline_data()
wp-admin/includes/template.php 348
do_action( 'add_inline_data', $post, $post_type_object );

Where the hook is used (in WP core)

Does not used.