Not sure which line is specifically the driver.
Guessing it uses driver for HP Officejet Pro 6830 E-all-in-one eventhough it is a 6970
Installed on this computer 2 years ago.
Just installed on the Macbook running same Linux. I can print but not scan with. Noticed that it wanted the 6830 driver so wanted to see if that was different from the one on the first computer (Dell)
$ sudo egrep -i "HP|6970|filter" /etc/cups/ppd/*
[sudo] password for tom:
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*%%%% PPD file for HP Officejet Pro 6830 with CUPS.
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*% (c) 2008 Copyright HP Development Company, LP
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*PCFileName: "hp-officejet_pro_6830.ppd"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*Product: "(HP Officejet Pro 6830 E-all-in-one)"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*Product: "(HP Officejet Pro 6835 E-all-in-one)"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*Manufacturer: "HP"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*ModelName: "HP Officejet Pro 6830"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*ShortNickName: "HP Officejet Pro 6830"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*NickName: "HP Officejet Pro 6830, hpcups 3.16.3"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*Throughput: "1"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*hpPrinterLanguage: "pcl3gui2"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*HPMechOffset: "71"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*1284DeviceID: "MFG:HP;MDL

fficejet pro 6830;DES

fficejet pro 6830;"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*cupsFilter: "application/vnd.cups-raster 0 hpcups"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*MediaType Glossy/HP Photo Papers: "<</MediaType/cupsMediaType 5>>setpagedevice"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*MediaType CoatedBrochure/HP Matte Brochure or Professional Paper: "<</MediaType/cupsMediaType 2>>setpagedevice"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*MediaType CoatedMatte/HP Matte Presentation Paper: "<</MediaType/cupsMediaType 2>>setpagedevice"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*MediaType BrochureGlosy/HP Glosy Brochure or Professional Paper: "<</MediaType/cupsMediaType 8>>setpagedevice"
/etc/cups/ppd/HP-OfficeJet-Pro-6970.ppd:*% End of hp-officejet_pro_6830.ppd, 44001 bytes.
/etc/cups/ppd/XP-400-Series.ppd:*cupsFilter: "application/vnd.cups-raster 0 /opt/epson-inkjet-printer-201203w/cups/lib/filter/epson_inkjet_printer_filter"
/etc/cups/ppd/XP-400-Series.ppd:*Throughput: "1"