Lane–Seifert Strand 3 — Amendment A3 to the joint preregistration (R5.6 FINAL, A1 and A2 DRAFT 8)

Prospective joint preregistration of Strand 3 of the Lane–Seifert programme, by Harald Zierhut and Thomas Schwarz. The deposit consists of the unchanged research plan R5.6 FINAL, the unchanged Amendment A1, and the reviewed Amendment A2 DRAFT 8, plus a new prospective author-release and precedence cover. The registered study compares Lane-type and Seifert-type likelihood constructions under controlled mean-map, covariance and prior-support choices. Amendment A2 prospectively adds a known-truth generator calibration, sensitivity to bias correction and redshift convention, artifact-only predictions, a JLA implementation check, production factorisation and box-gate provisions, and a historical sample-dependence target with explicitly documented configuration limitations. No study result, newly calculated study likelihood, posterior, evidence or unsealing is reported by this preregistration. Factorisation and box tests (F/B), numerical route checks and simulation qualification (2S) remain PRE-RUN requirements. The pre-publication status 'DRAFT 8' on the frozen A2 document identifies the reviewed source version; the dated author-release cover prospectively authorizes that exact version for this joint preregistration. The five canonical documents are provided separately. The sixth file is the complete, checksummed 31 October 2026 audit and transport archive, containing manifests, the D7-to-D8 diff, section-invariance checks, PDF quality checks and the independent cold-check records. Some historical provenance files remain unauthenticated and are explicitly marked as such. No third-party PIRSA source PDF is redistributed. Related records:Strand 1: https://doi.org/10.5281/zenodo.23161782Strand 2: https://doi.org/10.5281/zenodo.23692538