So having NEVER seen the mini NOR the campaign, the term 'warwagon' is a construct from early modern history where any wheeled convayance is up armored in some fashion for the purpose of providing cover during battle.
Essentially, it's the predecessor to the tank, but more closely associated with the WWI version (semi mobile bunker) than the modern post WWI versions. (Heavily armed and armored assault vehicle.)
I say if no rules are given, make it a bunker with wheels and give those 6 goblins a helluva an AC bonus/defensive modifier
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