Function: Escaping for HTML attributes.

Function: Register widget for sidebar with backward compatibility.

Function: Serves as an alias of wp_unregister_sidebar_widget().

Function: Registers widget control callback for customizing options.

Function: Alias of wp_unregister_widget_control().

Function: Remove user meta data.

Function: Retrieve user metadata.

Function: Update metadata of user.

Function: Retrieve HTML content of icon attachment image element.