Has anyone seen doco on the @whichfolders function ?

You can see this function being called in the 8.5 template to get a list of the folders a document belongs to, and I'm searching for information about it.

I'd like to know what the pre-reqs to using the function are (other than an 8.5 client on an 8.5 server with an 8.5 template)? Any ideas ?

Kind regards,

Adam