The global variable $_wp_post_type_features stores the features enabled for the different post types as a boolean value of the index $_wp_post_type_features[post_type][feature].
$_wp_post_type_features
add_post_type_support
By the Web Warlock, Wednesday, 28/Jul/2010 4:43
<?php add_post_type_support( $post_type, $feature ) ?>