Posterior likelihoods for the transition width Δ and the present-day dark energy equation of state w₀, marginalising the other, for models with a late-time phase transition in the dark energy equation of state. The blue dashed, red dotted, and black solid lines correspond, respectively, to Models B, C, and L described in the text. In all cases the Hubble constant has been kept fixed at H₀ = 70 km s⁻¹ Mpc⁻¹.