Some Z-Wave (and maybe Zigbee, but I'm not as familiar with most of those drivers) will report device firmware version under the "Data" section under "Device Details," or sometimes as "State Variables" or, probably least commonly, a "Current State" attribute, all of which are shown on the device page. However, there is no standard for this, so it's up to the driver author as to how they do this. I'm not sure most (or any?) built-in Hubitat drivers do this at all, and I've seen community drivers do all three. If you are writing your own driver and asking for that reason, my opinion is that the first option makes the most sense, but again, there is no standard.
For devices that are able to report their firmware version (i.e., that implement the relevant Z-Wave command classes), @bcopeland's Z-Wave Firmware Updater tool is able to get the current version--and, as the name suggests, update it if you have the files available on a web server, local or Internet, somewhere. This is a special driver you can apply to the device and use for the duration of your query/update, then switch it back to the "regular" driver. Nothing like this currently exists for Zigbee, but staff have indicated they are aware of the requests for both protocols (but all still depend on the manufacturer to actually provide firmware).
