Journalists discovered a certain “Pro mode” in the macOS Catalina 10.15.3 firmware code. This option is reported to allow
Essentially, in "Pro mode" the MacBook will reduceimpact of energy saving measures. As a result, your computer will run faster, but you will likely hear fan noise and drain the battery faster. Pro mode is supposed to turn off automatically the next day after being turned on. So there is no need to be afraid that you forgot to deactivate the mode and are loading the fan.
Which MacBooks will receive the new mode is still unknown. According to some reports, Pro mode may appear on the MacBook Pro 16 and future models.