The `allow_subdirectory_install()` function in WordPress allows users to determine if a subdirectory installation is permitted in a Multisite network setup
The `add_screen_option()` function in WordPress allows developers to create custom options for their plugins and themes by generating additional settings pages
The `add_network_option()` function in WordPress allows developers to add custom network options by passing in a `$network_id` parameter along with the option name and value
The `delete_site_transient()` function in WordPress removes a site transient from the database, which is temporary data stored across an entire network on a multisite installation