They can also reference shared directories on remote hosts or files and subdirectories within shared directories: their target is not mounted immediately at boot, but only temporarily on demand while opening them with the OpenFile() or CreateFile() API.
This refers to a system that allows access to shared directories on remote hosts, either directly or via files and subdirectories within those shared directories. The target directory is not mounted at boot time but becomes available upon demand when accessed through the OpenFile() or CreateFile() API.