WordPress at a glance
action is not described

wp-mail.php action-hook . WP 2.9.0

Fires to allow a plugin to do a complete takeover of Post by Email.

Usage

add_action( 'wp-mail.php', 'action_function_name_3516' );
function action_function_name_3516(){
	// action...
}

Where the hook is called

In file: /wp-mail.php
wp-mail.php
wp-mail.php 28
do_action( 'wp-mail.php' );

Where the hook is used (in WP core)

Does not used.