Comparison of the PSR J0337+1715 constraints of this paper with expected constraints from future gravitational wave observatories of a single binary neutron-star merger: Cosmic Explorer (CE; blue dotted curve) and Einstein Telescope (ET; blue dashed curve). CE and ET curves are taken from Fig. 9 in Shao et al. (2017). Like for the CE and ET curves, the PSR J0337+1715 curve is also based on EOS AP4. Solar System constraints (grey) are as in Fig. 11. JFBD gravity corresponds to β₀ = 0 (thin vertical line).