piano chord
G♭6
G♭1B♭3D♭5E♭6
A major triad with a sixth added. The same four notes as a minor seventh chord a third below.
Written the other way round it is F♯6 — the same twelve keys on a piano, a different piece of notation.
What is true of it
G♭6 is G♭, B♭, D♭ and E♭ — 1, 3, 5 and 6 counted from G♭.
These are also the notes of E♭m7/G♭ and D♯m7/G♭. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
On an instrument that cannot reach all 4, the 5 goes first, in that order.