This was probably not considered a hack when it was implemented but at some point in the early 2000s someone deployed two binary programs on an old Compaq rack

This was probably not considered a hack when it was implemented but at some point in the early 2000s someone deployed two binary programs on an old Compaq rack server running RedHat Linux of some version. I think they're called lpr and lpd. But I've tried to find their source and it's not in any major printer packages. By running strings and hexdump on them I think my co-worker finally managed to trace it to a package of software made for a firewall. And embedded in there were these two programs for printouts. SO that became well used in a major government branch that will go unnamed. Fast forward to 2013 and it's my job to upgrade it. Replace its hardware and its OS. Luckily the two binaries could be run from RHEL 6 but it was all on faith. I had no way to replace them or upgrade them because I had no idea what they did, what protocol they spoke. So they're running to this day. I'm sure someone here who is more versed in printing might tell me that they implement some standard protocol that can be replaced by CUPS or something well known. I'd be thankful but tbh they work so they won't be replaced in my time with these systems.