WordPress at a glance
action is not described

activate_wp_head action-hook . WP 3.0.0

Fires before the Site Activation page is loaded.

Fires on the 'wp_head' action.

Usage

add_action( 'activate_wp_head', 'action_function_name_9039' );
function action_function_name_9039(){
	// action...
}

Where the hook is called

do_activate_header()
activate_wp_head
wp-activate.php 95
do_action( 'activate_wp_head' );

Where the hook is used (in WP core)

Does not used.