Two key things that consumers want in a mobile, battery-powered device are the ability to work away from a power outlet for as long as possible, and charge quickly to replenish that power reserve. One of the reasons why Apple doesn't supply its mobile devices with fast chargers in the box is that the added heat causes additional wear on the battery.
Lithium batteries are under most strain when they're either fully charged or completely empty, so the company introduced a feature in iOS 13 called Optimized Battery Charging that will delay charging past 80 percent whenever it thinks you're going to leave your device plugged into a wall socket for an extended period of time.
Apple is now bringing that same functionality to MacBooks with a new feature in macOS Catalina 10.15.5, which is available to developers and beta testers for now.
Just like on iOS, the feature will be on by default and you'll be able to turn it off if you don't want to use it. It works by analyzing your charging routine and monitor battery temperature and processor loads to decide on how to modify the charging process to extend the lifespan of your MacBook battery.
Many use laptops plugged in almost all the time, which means the battery sits at nearly 100 percent capacity and trickle charges constantly, which isn't great for preserving battery health. The new battery management in macOS 10.15.5 is most helpful in those situations, and will change its behavior when you change your routine.
This doesn't affect the performance of your battery or your MacBook, and is likely the result of an important lesson that Apple learned over the iPhone throttling controversy. The company has been integrating faster and more power-hungry components in its newer MacBooks, and preserving battery health over the lifespan of your device will ensure it will support a high load on components without ever having to throttle them.
It's also worth noting that the new feature will only be available on MacBooks that support Thunderbolt 3, meaning MacBook Pro models from 2016 and MacBook Air models from 2018 or newer. That rules out all devices with a MagSafe connector.