I wouldn't be entirely surprised if it's actually there on all models and is just software enabled
I had a launch edition Mk V Golf that was missing the low fluid warning.
‘The internets’ reliably informed me you could software enable it, and the supplying dealer agreed with me.
At the first service they enabled it, but all that did was constantly shout the washer fluid was low, it did indeed require a sensor in the bottle that tapped into the loom.
I did eventually retrofit the sensor and bit of loom, after I’d had to remove the bumper to fit it.
I guess the washer fluid sensor just encourages up-selling to the Winter Pack.
Annoying, but I can see why they’d do it.