Pak Protecters in GURPS

[Bruno]

Kzinti STL flight was the gravity polarizer, which they were given by the 5-armed herbivores the Jotok. The Jotok made the deep tactical error of hiring stone age Kzinti to be their mercenary warriors in exchange for technological uplift. They promptly exterminated the mainstream Kzinti culture, which had at least achieved powered flight.

The Kzinti warriors turned on their employers when they discovered they were leaf eaters. Jotok imprint like ducklings, and the Kzinti domesticated them as engineers and food animals. There's a reason why Kzinti technology doesn't advance quickly - they're not very creative, and they tend to eat other races.

Anyways, this is why the Kzinti didn't recognize the Torch drive - they literally went from spears to the gravity polarizer, and then stagnated there.

As much as the Kzinti are poster children for hidebound and impulsive, they aren't totally stupid. Possibly a little stupid though.