There lies that ineffable effect in Debussy’s music that compels listening to it.
The spread chord at the very end of Claire de lune is a typical example of quality performance and an outstanding masterpiece, and it’s all about missing the D flat note.
It is all about applying chord extensions such as the 7th, 9th, and 11th chords, and the result is an amazing sound that is similar to none in music history.
The majestic chord at the end of the Claire de lune represents one of the most unique instances of Debussy’s Suite bergamasque.
Watch the whole piece being played by Katia Buniatishvili and pay attention to that last sequence at 4.50.
https://youtu.be/DBl2ClXzt3U