“LibrePods allows you to use AirPods features that are exclusive to Apple devices by implementing the proprietary protocol used to exchange data between AirPods and Apple devices.”
Someone reverse-engineered Apple’s secret AirPods protocol so Android and Linux users can get ear detection, noise control, and battery status. None of this is technically necessary. Apple just chose to wall it off to make the earbuds feel broken on anything but an iPhone. The features were always in the hardware you paid for. It took a stranger’s free time to give you the ones Apple decided you didn’t deserve.