Curved and Flat Indices

Question

However the indices chapter has no mention regarding "curved" and "flat". Are these just names or is there more to it? The Fierz transformation problem has something like

{\mu,\nu,\rho}::Indices(curved, position=fixed). {m,n,p,q,r,s,t,u,v}::Indices(flat, position=independent).

I don't understand the function of curved and flat

Answer 1

Those are just names; the full form of that first property is

 {\mu,\nu,\rho}::Indices(name=curved, position=fixed).