First and foremost, thanks @cmerwin for the thoughts on the headpiece. Second off, though, the beginning of
Path of Glory does show how Nova Cat warriors were attempting to prevent the wholesale slaughter of their civilian castes. It's interesting because even the Not-Named-Clan--Annihilated as it was--had its civilians sterilized and folded into all the other clans, whereas the books and sarna both state that millions of Nova Cat civilians had to be left behind and were all killed.
It's actually, now that I'm thinking about it, an interesting parallel. The clans invade, do damage, get hoist by their own petard at Tukayyid, and so the IS goes and inflicts the closest thing they can do to Clan judgment on a clan (but the Smoke Jaguars were the
worst, so y'know). But then the Clans feel slighted and savage the Nova Cats, to take out their own frustrations about Operation REVIVAL. At least, that's how I see it. It's still a
shocking waste of materiel to slaughter millions of civilians wholesale and abandon zellbrigen, but their pride was gravely wounded.
Finally, responding to @cmerwin's previous post re: Nova Cat society and population? While the main character is a hardass with PTSD, what we see of the Clan-in-the-IS in
Path of Glory, one gets the impression that unlike the Jade Falcons' sweeping architecture or the Ghost Bears' Great Works, Nova Cats are very deliberately austere. Canonically, they have no combat medals or awards, they seem to be tolerant of the Freeborn (though it may be because they were recently genocided), and they generally eschew overly-stylized Totem mechs. This might also explain why their worlds and factories were so easily repurposed.
Just a few thoughts.
Post Script edit:
I recall that in several instances, the Cats lost tacit Trials against some friendlier Clans
They did this to move into the Irece prefecture, losing a series of pitched 'trials' against the Dracs so they could be taken as abtakha without any loss of life or honor on either side. IIRC, there was some kind of sportsball game that the Nova Cats lost, and one that was decided by a coin toss wherein the Nova Cat called 'edge' while it was in the air. Definitely outside the intention of Clan law, but our visions do guide us to strange places.