What are stored on the “KG” drive? Last time my Mac had some startup problems and I went to the Genius Bar for a clean OS installation. The technician took out a hard drive called “KG” and booted my Mac from a recovery partition on it.

Just for curiosity, I want to know what are included on the “KG” drive. During booting, I saw a lot of normal and recovery partitions of different macOS versions. It would be interesting to know what other partitions/special tools are on the drive (and perhaps it would be handy for me to have a similar drive if I encountered similar problems again).

The only thing I know is the appearance. It should be a LaCie 2TB Rugged Thunderbolt + USB-C, with the “LACIE” trademark replaced by an Apple logo and the two uppercase characters “KG”. I think the words “Genius Bar” are also printed on it, if I recall correctly.

Any help is appreciated.
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.