Nothing in your screenshots is unusual or hidden. Those are perfectly normal files for a WordPress site and WordPress theme. The HTML of your pages is generated by that code. The developer documentation for WordPress is available here, if you want to learn about how themes and plugins are made, but you’ll want to have a basic knowledge of PHP first.
To add HTML to the <head> section of your site can be done in many ways, such as:
- Edit your theme’s
header.phpfile, and place the code between the<head>tags. This is not the recommended solution, unless your theme is custom developed entirely by you. This is because any changes made to a theme’s files will be lost of the theme is ever updated. - Create a child theme. Then copy your parent theme’s
header.phpfile to the child theme and edit that file to add the code between the<head>tags. - Use a plugin like Header and Footer Scripts or Tracking Script Manager. These plugins give you an area in the WordPress admin where you can add code like this to your site’s
<head>. - Add the following PHP code inside a custom plugin, or a Code Snippets plugin snippet:
add_action(
'wp_head',
function() {
echo '<link rel="manifest" href="https://wordpress.stackexchange.com/manifest.json"/>';
}
);