The Booster Fuel Supply is a module of the Boosting locomotion; it provides a particular functionality for its parent Booster. If it is disabled or removed, then the relevant boosting functionality will behave as by default. Most modules can optionally affect change globally (for both hands' Boosters). Booster modules can also depend upon conditions specified by their dependencies settings.
This module is responsible for supplying fuel. You can tweak the amount of fuel force that is started with, as well as the maximum amount. The supply can be enabled/disabled. When the supply is disabled (or deleted), it will be as though there is no fuel.