iPhone Guitar Tuner was a web tool linked at iphoneguitartuner.com. The August 14, 2007 entry named electric guitar, electric bass, steel-string acoustic guitar, cavaquinho and ukulele as instruments its tuning tool addressed.
The instrument is part of the setup
That list is the specific detail worth preserving. A tuning reference is useful only when the player knows which instrument and intended tuning it corresponds to. Similar-looking stringed instruments need not use the same pitches, so a list of supported instruments is more informative than a generic promise to tune anything.
The source does not explain whether this web tool played reference tones, listened through a microphone or used another interaction. It also does not name alternate tunings or a calibration setting. None of those features can be assumed from the word “tuner.”
Current functionality and accuracy have not been tested. This newly written historical overview preserves the original address and advertised instrument coverage without presenting a modern tuning method as a test of the 2007 product.