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 F♯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.