The G flat major ninth chord is a 5-note chord consisting of the notes Gb, Bb, Db, F and Ab.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Gbmaj9.
Chords that are a superset of Gbmaj9. The chords include more notes but always Gb, Bb, Db, F and Ab.
Chords that are a subset of Gbmaj9. These contain less notes but all of them are included in Gbmaj9.
In case you prefer a non-interactive variant of the chord chart, we've embedded a PNG image below that shows the notes for the the Gbmaj9 chord. Feel free to save or share the image as needed.