WordPress at a glance
filter is not described

xmlrpc_prepare_user filter-hook . WP 3.5.0

Filters XML-RPC-prepared data for the given user.

Usage

add_filter( 'xmlrpc_prepare_user', 'filter_function_name_9925', 10, 3 );
function filter_function_name_9925( $_user, $user, $fields ){
	// filter...

	return $_user;
}
$_user(array)
An array of user data.
$user(WP_User)
User object.
$fields(array)
An array of user fields.

Where the hook is called

wp_xmlrpc_server::_prepare_user()
wp-includes/class-wp-xmlrpc-server.php 1203
return apply_filters( 'xmlrpc_prepare_user', $_user, $user, $fields );

Where the hook is used (in WP core)

Does not used.