Check if an attribute is included to Global Catalog:
An example of querying Global Catalog
GC://servername.fabrikam.com/DC=sales,DC=fabrikam,DC=com
Find Global Catalog with the command line:
dsquery server -isgc
"CN=7-DEV-DE-DC16,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=other,DC=local"
Binding to the Global Catalog
https://learn.microsoft.com/en-us/windows/win32/ad/binding-to-the-global-catalog
GC://servername.fabrikam.com/DC=sales,DC=fabrikam,DC=com
Global Catalog
https://ldapwiki.com/wiki/Wiki.jsp?page=Global%20Catalog