Using WordPress ‘is_network_only_plugin()’ PHP function
Checks for “Network: true” in the plugin header to see if this should be activated only as a network wide plugin. The plugin would also work when Multisite is not…
HTTPS
Using WordPress ‘is_network_admin()’ PHP function
Determines whether the current request is for the network administrative interface.
Using WordPress ‘is_nav_menu_item()’ PHP function
Determines whether the given ID is a nav menu item.
Using WordPress ‘is_nav_menu()’ PHP function
Determines whether the given ID is a navigation menu.
Using WordPress ‘is_multi_author()’ PHP function
Determines whether this site has more than one author.
Using WordPress ‘like_escape()’ PHP function
Formerly used to escape strings before searching the DB. It was poorly documented and never worked as described.
Using WordPress ‘get_theme_update_available()’ PHP function
Retrieves the update link if there is a theme update available.
Using WordPress ‘is_month()’ PHP function
Determines whether the query is for an existing month archive.
Using WordPress ‘is_main_site()’ PHP function
Determines whether a site is the main site of the current network.