The startup routine for any app written in GenerAll, to define global variables. It would be delivered without a source, and there was some opis*.dbf to store its metadata, and gen_defg.prg to generate it. The idea was that it should contain all the generalia of the client company - name, address, phones etc, and those would be stored in global variables along with their checksum. When saving a record, if the checksum didn't match, it would consider the app to be in demo mode (IOW if anyone stole it, it would silently continue working for a while). When the record count in a specified table would exceed some magical number, it should simply refuse to save and say to call Avai at the phone number supplied.
Which happened only once, with the TaxiSys app. A copy was made on the side, which I thought was done by some savvy kid, who knew enough to change these variables, but didn't know enough to check where were they used, so the number of records in some transactional table exceeded 1000 and the alert.prg showed up with our phone number, and they called. Much later I understood it was probably Brlja who sold it without telling me. I should have suspected it right away.