Tuner
— the guitar has a built-in tuner.This feature is found mainly in models with a pickup (see the relevant paragraph); more traditional guitars can be equipped with external tuners, see "Packages" for details. Anyway, such a module is intended to simplify guitar tuning: the tuner “listens” to the sound of each string, determines whether it corresponds to the reference frequency, and if it does not match, it tells you in which direction there is a deviation. Thanks to this, even people who do not have fine hearing and special skills can cope with the setting without problems.
Note that built-in tuners usually have very simple, basic functionality, but in fact even this is often enough. And the undoubted advantage of such devices is that the tuner is not lost (more precisely, it can only be lost along with the guitar).