John Dalesandro

<p>The <strong>Head Trimmer</strong> plugin for WordPress is a customizable plugin to remove automatically generated information from the HEAD element across a site. These extras add bloat to a website and expose WordPress version information as well as other potential security signatures in the generated source code.</p>
<p>Removal options include:</p>
<ul>
<li>WordPress Version</li>
<li>WordPress Version from URLs for Scripts and Styles</li>
<li>Shortlink</li>
<li>Shortlink from HTTP response headers</li>
<li>Canonical</li>
<li>Relational Links for Posts Adjacent to Current Post</li>
<li>RSS Feeds</li>
<li>Really Simple Discovery Link for xmlrpc (rsd_link)</li>
<li>Windows Live Writer Manifest File Link (wlwmanifest_link)</li>
<li>oEmbed Discovery Links</li>
<li>REST API Link</li>
<li>REST API Link Header</li>
<li>Emoji Support</li>
<li>Global Styles and SVG Filters (duotone filters)</li>
<li>Gutenberg Block CSS Styles (or set ‘should_load_separate_core_block_assets’)</li>
<li>Classic Theme Styles (classic-theme-styles)</li>
<li>DNS Prefetch for //s.w.org</li>
<li>DNS Prefetch for Google Fonts //fonts.googleapis.com</li>
<li>jQuery</li>
</ul>


Head Trimmer

Customizable plugin to selectively remove WordPress version information, feeds, shortlinks, xmlrpc, emoji support and other miscellaneous extras from  …

Anand Kumar

Digital Liberation

<p>If you are running a WordPress site then sooner or later you need to insert some kind of code to your website. It is most likley a web analytics code like Google Analytics or may be social media script or some CSS stylesheet or may be Custom fonts. This plugin will do all the magic. Even if you want to insert those codes in a custom post type.</p>
<p>All you have to do is adding appropriate html code.</p>
<p>Don’t forget to wrap your code with proper tags.</p>
<pre><code><script type="text/javascript">
YOUR JS CODE HERE
</script>
</code></pre>
<p>Or for CSS:</p>
<pre><code><style type="text/css">
YOUR CSS CODE HERE
</style>
</code></pre>
<h4>Why use this plugin:</h4>
<ul>
<li>To insert CSS and JavaScript codes to <code><head></code> or before <code></body></code>.</li>
<li>To insert code to <code><head></code> of any single page or post.</li>
<li>To insert code to Custom Post Type [New Feature].</li>
</ul>
<p>The plugin should be compatible with WooCommerce.</p>
<h4>What it does not offer</h4>
<ul>
<li>You can’t insert/execute PHP codes.</li>
</ul>
<p>Almost all WordPress theme do support this “Header and Footer Scripts” plugin. If the codes are not appearing in your site [ask for support] or look at your theme file if they have standard <code>wp_head</code> and <code>wp_footer</code> hooks.</p>
<h4>Important Links</h4>
<p>For furhter information you are welcomed to follow these links:</p>
<ul>
<li><strong><a href="https://github.com/anandkumar/header-and-footer-scripts/wiki" rel="nofollow ugc">Read Documentation</a></strong></li>
<li><strong><a href="https://wordpress.org/support/plugin/header-and-footer-scripts/" rel="ugc">Get Support</a></strong></li>
<li><strong><a href="https://github.com/anandkumar/header-and-footer-scripts" rel="nofollow ugc">GitHub Repository</a></strong></li>
</ul>


Header and Footer Scripts

good

Como es posible que al desinstalar el plugin, si no has borrado el script te deje el código ahi metido. Y luego a averiguar de donde vienen los errores. 

Al desinstalar te deja el código

Header and Footer Scripts plugin allows you to add scripts to WordPress site's  and just before closing  tag.

Head Trimmer vs Header and Footer Scripts