Gas units - Kwh vs m3

I see that the data in the MQTT field contains a unitofmeasure field.

In my case, the unit is Kwh - so presumably that is supplier dependant? Some might report in m3 for instance?

The conversion between volume and kwh seems to be dependant on a conversion factor that may change as the temperature and gas supply changes....but my gas bill contains volume measurements.

Does the fact that the meter is reporting in kwh mean that their volume calculation is based on kwh, or does the meter also report in m3, and that is not currently available over MQTT?