Asymptotic mean value Laplacian on equiregular sub-Riemannian manifolds

Let $(M,\mathcal{D},g)$ be a smooth equiregular sub-Riemannian manifold equipped with a smooth positive measure $μ$. We study the small-scale limit of the metric-ball mean-value operator \[ A_hf(x)=\frac{1}{h^{2}μ(B(x,h)) }\int_{B(x,h)}(f(q)-f(x))\, dμ(q). \] Exact homogeneity yields the pointwise