The 68% and 95% highest-density credible regions of the PSR J0030+0451 likelihood function (normalized by a flat joint density) are bounded by the blue contours: the ST+PST model is featured in the upper panels, and the ST+CST model is featured in the lower panels. The black contours are identical to those shown in Figure 1, being associated with a population-level prior transformed to mass–radius space; here we show how this prior is updated as a result of our analysis of PSR J0030+0451. To provide context, we are considering the implications for a hypothetical future analysis of data from a different pulsar ﹩{ \mathcal S }﹩ (i.e., not PSR J0030+0451). We assume that the EoS of all matter (core to crust) is shared between ﹩{ \mathcal S }﹩ and PSR J0030+0451; as a joint prior for the EoS of matter in ﹩{ \mathcal S }﹩, we thus invoke the joint posterior distribution of EoS parameters conditional on NICER observations of PSR J0030+0451. We assume the central density of ﹩{ \mathcal S }﹩ is drawn from the same population-level density ﹩p({\varepsilon }_{c}| \mathrm{EoS})﹩ as PSR J0030+0451. We then transform the joint prior of the EoS parameters and central density of ﹩{ \mathcal S }﹩ to the joint space of the mass and radius of ﹩{ \mathcal S };﹩ we render the two-dimensional regions enclosing 68% and 95% of the updated prior mass in green. We note that the updated prior distributions are still mostly dominated by the prior for PSR J0300+0451, with slightly more support for higher radii in the ST+CST model.