ScopedBaseDDLLock private constructor third parameter is called StringData resName which stands for Resource Name.

This resource name is passed and stored under _resourceName which is then ONLY used to as a second parameter of lock and unlock of the _lockManager.

For these two methods, the third parameter which accepts a StringData is marked as ns which makes me think this could accept a NamespaceString.
It's then used in the DDLLockManager::_registerResourceName and passed to a DDLResourceName.