A few small apps for practicing — each one opens full-screen on its own page.
A chromatic tuner and a metronome in one — tap tempo, time signatures, and subdivisions on one side; mic-based pitch detection with a cents gauge on the other.
A practice timer — build a session with up to 6 focuses (name, notes, resources) and it splits a 20-minute block evenly across them, auto-advancing as you go.
An interactive guitar fretboard in standard tuning — pick a note to see every spot it lives on the neck, or show all notes at once.