I always thought it meant that it was meant it was like the hubs are always locked in, just normally unpowered.
Most of the chain drive tractors with a jackshaft were homebuilt rigs made from a old car to increase the wheelbase. However some really old tractors had a small gear that drove a bigger ring gear inside the wheel, so I guess they would be a non live axle by your diffination too.
However you cut it Danger FX4 Ranger, you don't have any hubs to worry about.