Apple is apparently working on a new feature that will allow users of its laptops to temporarily boost the performance of their devices. As spotted by 9to5Mac, the latest beta version of macOS Catalina contains strings that refer to something called Pro Mode.
The image shown in the report shows a few strings referring to this new mode, including one that says “Apps may run faster, but battery life may decrease and fan noise may increase”. Another message says “Fan speed limit overridden”, which makes it pretty clear that the feature will allow the fan speeds to go beyond the usual limit in order to keep the system cool in this high-performance state. This makes some sense, as this mode is probably not meant for extended use, and those that really need it will probably be fine with additional noise for a short period of time. The image further shows that the fan speed will be reset the day after Pro Mode is enabled.
While that's all we see in the image, the report further suggests that the feature will be exclusive to MacBooks, so you won't be seeing this in Apple's desktop computers. It also seems like it might be exclusive to devices that make use of the new thermal design, which Apple debuted in the 16-inch MacBook Pro last year. Apple could be announcing a 13-inch variant of the MacBook Pro in the coming months, which would be a good time for the feature to be announced.
Aside from that, the name of the feature itself could be an indicator of its availability, so regular MacBooks and MacBook Air might not be able to use it either. Of course, until the feature is officially announced, there's no way of knowing exactly what Apple is planning.