GuitarFretboardTrainer appGuitarFretboardTrainer is Science & Education tool that is open source under the GPL-2.0-only license. A very simple way to learn all the notes on the guitar fretboard by being quizzed.
It's easy to add to your daily guitar practice.
Pick the string you want to learn, which frets you want to learn the notes for and go for it!
You can practice finding a note on a string.
e.g. Find G# on the E string. The answer is Fret 4.
You can practice answering what note is at a certain fret.
e.g. What note is on the E string at Fret 5?