E2 · A2 · D3 · G3 · B3 · E4
Standard tuning, low to high: E2, A2, D3, G3, B3 and E4. Play any open string and fork works out which one you meant, then shows how far off you are. It holds its choice while you turn the peg rather than jumping to a neighbouring string halfway through.
The low E is the one that catches tuners out, because pitch detection often locks onto the octave above it. Fork snaps that back down, so 165 Hz is read as the 82 Hz you are actually playing.
Tap any of the six dots to hear that string played back, which is useful for tuning by ear or checking an open chord once you are done.