I will talk about the dynamics of different facets of the speed of light in
Palatini theories of gravity in a special frame.
In this frame, the affine connection vanishes and it has been shown before
that such frame, shows a broken degeneracy and a possible dynamics for
different facets of the speed of light. Choosing an f(R,R_mn R^mn) model, I check if different observational constraints are in agreement with this claim.