Fuel burn data source

Where does the fuel burn data come from?
For example for Embraer-E2 I was able to find this document

it shows range, capacity, but doesn’t say anything about fuel burn.

You can define it on the payload range chart, fuel cap and a few weights.
The chart’s last segment is max fuel, the 2nd is a tradeoff payload for fuel, the first horizontal segment is TOW<MTOW. Put all this in a formula and you’re there - simplified and static of course.