Function: Checks that the taxonomy name exists.

Function: Check if Term exists.

Function: Determines whether the current admin page is generated by a plugin.

Function: Update the categories cache.

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.