WordPress at a glance
action is not described

deprecated_function_run action-hook . WP 2.5.0

Fires when a deprecated function is called.

Usage

add_action( 'deprecated_function_run', 'action_function_name_3595', 10, 3 );
function action_function_name_3595( $function, $replacement, $version ){
	// action...
}
$function(string)
The function that was called.
$replacement(string)
The function that should have been called.
$version(string)
The version of WordPress that deprecated the function.

Where the hook is called

_deprecated_function()
wc_deprecated_function()
wp-includes/functions.php 3883
do_action( 'deprecated_function_run', $function, $replacement, $version );
woocommerce/includes/wc-deprecated-functions.php 47
do_action( 'deprecated_function_run', $function, $replacement, $version );

Where the hook is used (in WP core)

wp-includes/rest-api.php 160
add_action( 'deprecated_function_run', 'rest_handle_deprecated_function', 10, 3 );