While I wait for Photo8x10 to reply...

Fuji AG Guard is basically a same product as AGFA Sistan. To use, dilute it according to the instructions and soak your print AFTER COMPLETE WASH for a minute or two and squeegee the excess, then let dry. It is supposed to actively protect silver in the emulsion. I have the AGFA version of the product but rarely use it.

Interestingly enough, when used with FB paper, it prevents paper from curling so much.