Using WordPress ‘get_network()’ PHP function
Retrieves network data given a network ID or network object.
Network
Using WordPress ‘get_subdirectory_reserved_names()’ PHP function
Retrieves a list of reserved site on a sub-directory Multisite installation.
Using WordPress ‘is_wpmu_sitewide_plugin()’ PHP function
Deprecated functionality for determining if the current plugin is network-only.
Using WordPress ‘is_main_site()’ PHP function
Determines whether a site is the main site of the current network.