Phenomenological Gauss-Bonnet braneworld leakage model for high‑ℓ CMB suppression. Includes CAMB/CLASS patches, MCMC scripts, and reproducible pipelines for Planck, ACT DR6, and SPT‑3G data.

We provide a consistent description of the reheating era of a constrained Gauss-Bonnet model by using the same free parameters that result in a viable inflationary era. The theory predicts a propagation velocity of tensor perturbations which is equal to unity in order to be in agreement with the GW170817 event. The reheating era turns out to be …