What is remarkable here is that Stuart knows the 22-metre long HAWv A5 Juggernaut. The A5 first showed up in West End Games’ Imperial Sourcebook in 1990. The visual design of the vehicle was based on Joe Johnston’s concept art for The Empire Strikes Back. Since then it popped up sporadically in unlikely locations such as Dark Horse Comics’ Star Wars: Empire issue 29.
Most fans are familiar with is the larger 49-metre long HAWv A6 variant – the so-called “clone turbo tank“. This is because the A6s were featured in the 2005 film Revenge of the Sith Later, they also showed up in Star Wars The Clone Wars animated series. As such, all the toys and visual encyclopaedias refer mostly to the A6.
There is no reason why Stuart would bring up the A5, even if he’s read the wiki thoroughly.
Unless he plays West End Games’ Star Wars The Roleplaying Game and has or had used it in his RPG campaign.
Remarkable.