Using WordPress ‘is_object_in_taxonomy()’ PHP function
Determines if the given object type is associated with the given taxonomy.
PHP
Using WordPress ‘is_nav_menu()’ PHP function
Determines whether the given ID is a navigation menu.
Using WordPress ‘is_multisite()’ PHP function
The article provides an introduction to the function in WordPress, which determines whether Multisite mode is enabled or not
Using WordPress ‘is_main_blog()’ PHP function
Deprecated functionality to determin if the current site is the main site.