Modern electronic speed controllers (ESCs) have a huge variety of settings and tuning options. It can be pretty intimidating, honestly, to dig into some of them and attempt to figure out which ones are helpful and how to set them.
So, many stock and entry-level RC racing classes require that your ESC be in blinky mode which means that it does not use any artificial motor timing advancement including boost or turbo. This helps to even the playing field for all the racers, and it lets you not worry so much about the ESC and focus on tuning your car in other ways.
See our article on electronic speed controller for more info on ESC settings.