Recently, I acquired a Brother MFC printer (Brother MFC-L8610CDW), and have installed the appropriate Brother "driver" packages to use it under CUPS.
One of the packages (the brmfcfaxdrv-2.0.2 "Fax" driver package) includes a commandline user script ("brpcfax") to "print to fax", that seems to have been written by someone with only a rudimentary concept of what users would use it for. Written not in POSIX shell, but in bash, it queues documents to a fixed-name print queue ("BRFAX") to be faxed by the printer attached to this queue.
