This Addon is for updating the firmware for USB-sticks and build in chips. The documentation
states that it only supports Zigbee/OpenThread Multiprotocol container for Silicon Labs based radios.
Silicon Labs Z-Wave units is also used like in the Aeotec Z-Stick 7 (ZST10-700 by Silicon Labs) a EFR32ZG14 CP2102N SUB UART Bridge Controller.
It would be a good thing to make this Addon also handle Silicon Z-Wave USB sticks so this sticks also can get firmware updated by the addon.
This is an interesting thing, but be aware the Z-Wave sticks are an entirely different chipset, completely different radios. They use completely different frequencies and a completely different SDK.
Si Labs may own the Z-Wave protocol information, but that does not mean it is anywhere near compatibale with Zigbee or Thread, because it just is not. Z-Wave uses a different frequency depending on the location and the Z-Wave radios are locked to that frequency, except 700 series chips which can change a limited number oftimes. Z-Wave uses sub 1GHz frequencies, Zigbee and Thread use 2.4GHz. The SiLabs Z-Wave radio is an entirely different chip to their Zigbee/Thread radio chip.
Zigbee and Thread use 2.4GHz and both use radios based on IEEE 802.15.4. Z-Wave is a completely different radio and is not based on this.
Given this, it would actually be highly confusing and actually very silly to integrate Z-Wave into an add–on that uses an entirely different radio, entirely different protocol and entirely different SDK.
Might be better to do a feature request at Z-wave JS to allow Z-Wave JS to be able to modify region for Z-Wave 700 series and above chipsets and not try to add it to a completely incompatible radio.