What are stored on the “KG” drive?
There's no way anyone here can know what exactly was stored on a specific hard drive handled by an unspecified technician in an unspecified location. You should ask the technician if you can instead.

The contents on that hard drive has most possible changed numerous times between then and now. There's no guarantee in any form that any "KG" drive has the same contents as any other "KG" drive across countries, stores, technicians, etc.

In practical reality, there's really no chance for you to get an exact copy of that technicians hard drive at the time of your repair.

Moderne Macs have recovery partitions on their hard drives or SSD by standard. They also contain internet recovery within the flash portion of their main board - so even if you replace the hard drive or SSD, you'll be able to boot from that and reinstall macOS or alternatively fix problems with the drive.