WordPress Version: 5.5
/**
* Registers a selection of default headers to be displayed by the custom header admin UI.
*
* @since 3.0.0
*
* @global array $_wp_default_headers
*
* @param array $headers Array of headers keyed by a string ID. The IDs point to arrays
* containing 'url', 'thumbnail_url', and 'description' keys.
*/
function register_default_headers($headers)
{
global $_wp_default_headers;
$_wp_default_headers = array_merge((array) $_wp_default_headers, (array) $headers);
}