No 'user' example in demo.php

for other’s reference, I’m using this:

array(
	'name'        => 'Players',
	'id'          => "players",
	'type'        => 'user',
	'field_type'  => 'select_advanced',
	'multiple'		=> TRUE,
	'query_args'  => array('meta_key'     => 'is_player',
		'meta_value'   => 'on')//'role'    => 'player'//role worked, but I stopped using the role for these.
	),

https://wordpress.org/plugins/meta-box/