The G flat minor/major ninth chord is a 5-note chord consisting of the notes Gb, Bbb, Db, F and Ab.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as GbmM9.
Chords that are a subset of GbmM9. These contain less notes but all of them are included in GbmM9.
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 GbmM9 chord. Feel free to save or share the image as needed.