This looks like a fuel mix/ecu modifier, as opposed to an ethanol catalyst to produce hydrogen additive, or are there other components not shown?
On closer examination, I think you are right in your suggestion.
I believe these things increase the fuel injection period via the ecu, when fuel with high concentrations of ethanol is used. However, as fuel economy suffers with ethanol, not sure of the financial advantage. Apparently, some states in the U S look at them as illegal because it counts as interfering with a vehicle’s emissions.