ΛCDM is a successful effective description of cosmic structure and acceleration but leaves the dark sector phenomenologically unexplained. VBRC (Visibility-Based Reality Construction) reinterprets dark matter and dark energy as the two unread-sector readouts of a dual-Schur reduction of an underlying observer-relative theory: a single structural calibration parameter c controls both galactic and cosmic acceleration scales. This work presents a joint test of the structural prediction c = 1 against five observational gates: SPARC radial acceleration relation, cosmic chronometers, Pantheon+ supernovae, DESI 2024 BAO (with sound-horizon marginalization), and the Planck 2018 compressed CMB shift parameter. The inverse-variance joint constraint yields cVBRCʲoint = 1. 007 ± 0. 006, corresponding to Δχ² (c=1) ≈ 1. 4 (~1. 2σ) — fully consistent with the structural prediction. A master tension spectrum across eight robustness variants (rd-marginalized 6-gate including DES-SN5YR and DES Y3 WL, fixed-rd stress configurations, H₀ sensitivity, Ωb h² robustness) confirms the result is not a coincidence of any single dataset. The companion numerical pipeline is archived at DOI: 10. 5281/zenodo. 20301740.
Yunbeom Yi (Wed,) studied this question.