My October 2023-built Fabia was bought from a Skoda dealership's showroom and came with the standard 12V inflator and container of sealant. If I had ordered the car myself, I would have specified that the optional spare-wheel package be included.
There APPEAR to be two spare-wheel options (both costing £150 when ordered for a new car).
1: A steel spare wheel (for 15" wheels) with tool kit and jack and an original equipment tyre.
2: An emergency space-saving spare wheel (for 16"-18" wheels) with tool kit and jack and a space-saving spare wheel.
I asked the dealership to obtain the optional spare wheel 'kit' for my Fabia SE L (that has 16"-diameter alloy wheels) and the 1st type (for £200) was provided. My car has Goodyear 195/55 R16 91V tyres, whereas the 15"-diameter steel spare wheel carries a Nexen 185/65 R15 88H tyre. Obviously neither that steel wheel nor its Nexen tyre match the alloy wheels and Goodyear tyres fitted to the car's other four wheels, but the rolling circumference of 195/55 Ri6 and 185/65 R15 tyres is near as dammit the same. So - if I have to bring the spare wheel into play - the car's handling should not be much affected and the distance and speed limitations that bedevil space-saver tyres won't apply.
As the rolling circumference of the 17"-diameter and 18"-diameter wheels fitted to some Fabias (as standard or optionally) is greater than that of the 15" and 16" wheels, It's possible that a wheel fitted with a 215/45 R17 or 215/40 R18 tyre would not fit in the spare-wheel well, which might explain why there are two spare wheel options.
Anyway, as far as the sealant/inflator is concerned, I initially considered removing the purpose-designed polystyrene 'box' in which the jack and tools are tidily stored and put the jack, tools, sealant and inflator into a bag and store the lot inside the spare wheel. This offended my OCD though and, as i was going to carry other stuff (torque wrench, sockets, fire extinguisher, Glock 30, etc.) in a couple of bags to be kept in the boot, I just added the sealant and inflator. I've also DIYed a couple of 'pullers' to remove the Aero wheel trims more easily.
(Unusual that all current Fabia models (including the quite-quick Monte Carlo) are said to have rear drum brakes. Probably doesn't matter much I suppose as the front brakes do all the work and there's a sporting chance the handbrake will be more effective.)