Avoids a collision between a site slug and a permalink slug.

Mark allowed redirect hosts safe for HTTP requests as well.

Learn how to use the WordPress 'admin\_created\_user\_email()' PHP function to send customized notifications to newly-created users.

Determines whether the current post is open for comments.

Accepts matches array from preg_replace_callback in wpautop() or a string.

​The `display_header()` function in WordPress adds the installation header with optional body classes passed as a parameter

Learn about the WordPress `deslash()` function, which removes unnecessary backslashes from strings, in this informative article

​The `delete_user_option()` function in WordPress allows deleting user options with a global blog capability

Adds an additional class to the browser nag if the current version is insecure.