Oh! Those two little lower bout braces look interesting! I have seen similar on flamenco guitars but never knew why they are necessary there, especially when shaved very thin they seem to have "almost" no support function. Very cool.
Ralf
Ralf, since the goal is a very sharp, focused sound without a lot of sustain, they are supposed to help control the sound, with interfering with the, as Somogyi would say, cross-dipole movement that is desired for flamenco guitars. (Basically, the center is able to move in multiple directions.)
And even though they may be shaved thin, they can still provide quite a bit of cross grain support. When I built my classical, I used open harmonic bars to extend braces under and through them, opening up the top half of the soundboard. What Jeffrey Elliott discovered is that strips as low as 0.5mm tall in those open areas provided a lot of strength against through cracks which can be common in that design. I wouldn’t go that low with these, since they are also acting as stop bars.