Yup, that is definitely not in the ads or documentation. The best way would be to get a copy of the ESC source code, a debugger for the microprocessor used, a logic analyzer, an oscilloscope... and by that point, you could have written your own code from scratch.

We haven't mentioned yet that if you are using a digital radio (and who isn't these days?), there is a small possibility that the resolution of the entire signal chain could be limited by the radio. But my guess is that the PWM algorithm or hardware in the ESC is the limiting factor, especially given the trend toward ever-higher drive frequencies.

P.S. All of this may not matter if you drive like me, with your trigger finger shaking.