This are default settings fron WordPress.
This was set via wp-includes/default_filters.php or the feed inside your theme.
Check the theme, functions.php for
add_theme_support( 'automatic-feed-links' );
and remove it.
Add this via plugin or functions.php in your theme for remove the different defaults, hints and small description is on the source.
remove_action( 'wp_head', 'feed_links_extra', 3 ); // Display the links to the extra feeds such as category feeds
remove_action( 'wp_head', 'feed_links', 2 ); // Display the links to the general feeds: Post and Comment Feed
remove_action( 'wp_head', 'rsd_link' ); // Display the link to the Really Simple Discovery service endpoint, EditURI link
remove_action( 'wp_head', 'wlwmanifest_link' ); // Display the link to the Windows Live Writer manifest file.
remove_action( 'wp_head', 'index_rel_link'); // index link
remove_action( 'wp_head', 'parent_post_rel_link', 10, 0 ); // prev link
remove_action( 'wp_head', 'start_post_rel_link', 10, 0 ); // start link
remove_action( 'wp_head', 'adjacent_posts_rel_link_wp_head', 10, 0 ); // Display relational links for the posts adjacent to the current post.
remove_action( 'wp_head', 'wp_generator' ); // Display the XHTML generator that is generated on the wp_head hook, WP version