Using WordPress ‘is_new_day()’ PHP function
Determines whether the publish date of the current post in the loop is different from the publish date of the previous post in the loop.
HTTPS
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…
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.