I was trying to use the File_As field to store some information and found that the field would be populated with the Author, Year, and Title of the record if I used BiblioWeb to edit it online. It didn't matter what field I was changing, and if I tried to edit the File_As field, it would ignore my edit and retain the Author, Year, Title info. It even happened when I switched to using another field - the File_As field would be populated when I saved edits to the record. Fortunately, I can web post hide the File_As field so it never has to be seen by anyone, but I can't imagine this behavior is intentional, as I thought the File_As field was supposed to allow one to create their own tag...
In Biblioscape desktop, you
In Biblioscape desktop, you can change that field. You can use another field like "Label" to file records in other ways. Biblioscape will stamp the File_as field to make it unique. So it can be used as a key if user chose to use "natural citation" (database independent temp citation).