WordPress at a glance
action is not described

post_action_(action) action-hook . WP 4.6.0

Fires for a given custom post action request.

The dynamic portion of the hook name, $action, refers to the custom post action.

Usage

add_action( 'post_action_(action)', 'action_function_name_7272' );
function action_function_name_7272( $post_id ){
	// action...
}
$post_id(int)
Post ID sent with the request.

Where the hook is called

In file: /wp-admin/post.php
post_action_(action)
wp-admin/post.php 311
do_action( "post_action_{$action}", $post_id );

Where the hook is used (in WP core)

Does not used.