WordPress at a glance
action is not described

do_favicon action-hook . WP 5.4.0

Fired when the template loader determines a favicon.ico request.

Usage

add_action( 'do_favicon', 'action_function_name_4051' );
function action_function_name_4051(){
	// action...
}

Changelog

Since 5.4.0 Introduced.

Where the hook is called

In file: /wp-includes/template-loader.php
do_favicon
wp-includes/template-loader.php 45
do_action( 'do_favicon' );

Where in WP core the hook is used

wp-includes/default-filters.php 341
add_action( 'do_favicon', 'do_favicon' );