A MacBook that stays on its adapter spends its life at 100%, where a lithium-ion cell ages fastest. Kombucha holds the battery inside a range you choose: it stops charging at the upper threshold and resumes at the lower one, so the Mac runs from the adapter while the battery rests. Also: Charge to 100% Once, Heat Protection, discharge to the limit, history charts, battery health. Free and open source (MIT), no network access or telemetry. Apple Silicon, macOS 15–26.