performance.php

<?php
/**
 * Disable header links
 */

 /**
  * Clean up wp_head()
  *
  * Remove unnecessary <link>'s
  * Remove inline CSS and JS from WP emoji support
  * Remove inline CSS used by Recent Comments widget
  * Remove inline CSS used by posts with galleries
  * Remove self-closing tag
  *
  * You can enable/disable this feature in functions.php (or app/setup.php if you're using Sage):
  * add_theme_support('soil-clean-up');
  */
 function ggn_head_cleanup() {
   // Originally from http://wpengineer.com/1438/wordpress-header/
   remove_action('wp_head', 'feed_links_extra', 3);
   add_action('wp_head', 'ob_start', 1, 0);
   add_action('wp_head', function () {
     $pattern = '/.*' . preg_quote(esc_url(get_feed_link('comments_' . get_default_feed())), '/') . '.*[\r\n]+/';
     echo preg_replace($pattern, '', ob_get_clean());
   }, 3, 0);
   remove_action('wp_head', 'rsd_link');
   remove_action('wp_head', 'wlwmanifest_link');
   remove_action('wp_head', 'adjacent_posts_rel_link_wp_head', 10);
   remove_action('wp_head', 'wp_generator');
   remove_action('wp_head', 'wp_shortlink_wp_head', 10);
   remove_action('wp_head', 'wp_oembed_add_discovery_links');
   remove_action('wp_head', 'wp_oembed_add_host_js');
   remove_action('wp_head', 'rest_output_link_wp_head', 10);
   add_filter('use_default_gallery_style', '__return_false');
   add_filter('show_recent_comments_widget_style', '__return_false');
 }
 add_action('init', 'ggn_head_cleanup');

remove_action('wp_head', 'start_post_rel_link');
remove_action('wp_head', 'index_rel_link');
remove_action('wp_head', 'adjacent_posts_rel_link');
remove_action('xmlrpc_rsd_apis', 'rest_output_rsd');
remove_action('template_redirect', 'rest_output_link_header', 11);

/**
 * Disables trackbacks/pingbacks
 *
 * You can enable/disable this feature in functions.php (or app/setup.php if you're using Sage):
 * add_theme_support('soil-disable-trackbacks');
 */
/**
 * Disable pingback XMLRPC method
 */
function ggn_filter_xmlrpc_method($methods) {
  unset($methods['pingback.ping']);
  return $methods;
}
add_filter('xmlrpc_methods', 'ggn_filter_xmlrpc_method', 10, 1);
/**
 * Remove pingback header
 */
function ggn_filter_headers($headers) {
  if (isset($headers['X-Pingback'])) {
    unset($headers['X-Pingback']);
  }
  return $headers;
}
add_filter('wp_headers', 'ggn_filter_headers', 10, 1);
/**
 * Kill trackback rewrite rule
 */
function ggn_filter_rewrites($rules) {
  foreach ($rules as $rule => $rewrite) {
    if (preg_match('/trackback\/\?\$$/i', $rule)) {
      unset($rules[$rule]);
    }
  }
  return $rules;
}
add_filter('rewrite_rules_array', 'ggn_filter_rewrites');
/**
 * Kill bloginfo('pingback_url')
 */
function ggn_kill_pingback_url($output, $show) {
  if ($show === 'pingback_url') {
    $output = '';
  }
  return $output;
}
add_filter('bloginfo_url', 'ggn_kill_pingback_url', 10, 2);

function no_self_ping( &$links ) {
    $home = get_option( 'home' );
    foreach ( $links as $l => $link )
        if ( 0 === strpos( $link, $home ) )
            unset($links[$l]);
}
add_action( 'pre_ping', 'no_self_ping' );

//Remove jquery migrate

function twf_remove_jquery_migrate( $scripts ) {
	if ( ! is_admin() && isset( $scripts->registered['jquery'] ) ) {
		$script = $scripts->registered['jquery'];

		if ( $script->deps ) { // Check whether the script has any dependencies
			$script->deps = array_diff( $script->deps, array( 'jquery-migrate' ) );
		}
	}
}
add_action( 'wp_default_scripts', 'twf_remove_jquery_migrate' );

/**
 * Disable XMLRPC call
 */
function ggn_kill_xmlrpc($action) {
  if ($action === 'pingback.ping') {
    wp_die('Pingbacks are not supported', 'Not Allowed!', ['response' => 403]);
  }
}
add_action('xmlrpc_call', 'ggn_kill_xmlrpc');

/**
 * Remove the WordPress version from RSS feeds
 */
add_filter('the_generator', '__return_false');

add_filter('xmlrpc_enabled', '__return_false');



/**
 * Disable the emoji's
 */
function disable_emojis() {
 remove_action( 'wp_head', 'print_emoji_detection_script', 7 );
 remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
 remove_action( 'wp_print_styles', 'print_emoji_styles' );
 remove_action( 'admin_print_styles', 'print_emoji_styles' );
 remove_filter( 'the_content_feed', 'wp_staticize_emoji' );
 remove_filter( 'comment_text_rss', 'wp_staticize_emoji' );
 remove_filter( 'wp_mail', 'wp_staticize_emoji_for_email' );
 add_filter( 'tiny_mce_plugins', 'disable_emojis_tinymce' );
 add_filter( 'wp_resource_hints', 'disable_emojis_remove_dns_prefetch', 10, 2 );
}
add_action( 'init', 'disable_emojis' );

/**
 * Filter function used to remove the tinymce emoji plugin.
 *
 * @param array $plugins
 * @return array Difference betwen the two arrays
 */
function disable_emojis_tinymce( $plugins ) {
 if ( is_array( $plugins ) ) {
 return array_diff( $plugins, array( 'wpemoji' ) );
 } else {
 return array();
 }
}

/**
 * Remove emoji CDN hostname from DNS prefetching hints.
 *
 * @param array $urls URLs to print for resource hints.
 * @param string $relation_type The relation type the URLs are printed for.
 * @return array Difference betwen the two arrays.
 */
function disable_emojis_remove_dns_prefetch( $urls, $relation_type ) {
 if ( 'dns-prefetch' == $relation_type ) {
 /** This filter is documented in wp-includes/formatting.php */
 $emoji_svg_url = apply_filters( 'emoji_svg_url', 'https://s.w.org/images/core/emoji/2/svg/' );

$urls = array_diff( $urls, array( $emoji_svg_url ) );
 }

return $urls;
}