piano chord
G♯13
G♯1B♯3D♯5F♯♭7A♯9E♯13
Seven notes in theory and four or five in anyone’s hands: root, third, seventh and thirteenth carry it.
Written the other way round it is A♭13 — the same twelve keys on a piano, a different piece of notation.
What is true of it
G♯13 is G♯, B♯, D♯, F♯, A♯ and E♯ — 1, 3, 5, b7, 9 and 13 counted from G♯.
On an instrument that cannot reach all 6, the 5, 9 and 1 go first, in that order.