Does this chord function as a 13 chord?

Question

In Debussy's La Fille aux Cheveux de Lin, there is this passage:

(Debussy: Préludes Livre I, No. 8, bar 24) The piece is in Gb major.

This first chord is probably a I chord. But since it has that extra Eb, does it mean it's a I13 chord, despite the fact it has no other notes from that extension? Or is it just a normal I chord with some decoration?

The other option is that it's vi7b chord. Is this more likely?

Answer 1

Every single chord in this measure is an Ebm7, in various inversions and voicings.

Answer 2

A 13th chord usually has a dom 7 in it. Without that you will not hear the typical 13th chord sound. It is however a maj 6 chord {1, 3, 5, 6}. Sometimes the 5th is omitted but doesn't need to be if the voicing avoids a maj 2nd, e.g. {5, 1, 3, 6}.