ReadonlydeterminismThe §33 tier the world asked for.
Readonlydimension"2d" or "3d" (§21).
ReadonlygravityResolved world gravity, m/s² (§21, Appendix A).
ReadonlysleepingResolved §32 sleeping configuration.
Optional Readonlysolver§28 solver iterations, when the world set them (absent = solver default).
The world configuration recorded in a PhysicsSnapshot (§34).
Every field here changes what stepping the restored bytes produces, so a mismatch means the restored run is not a continuation of the captured one — the §33/§34 promise — even though the adapter would deserialize the bytes without complaint. Gravity is the resolved 3-tuple, sleeping the resolved §32 record (Appendix A defaults filled in), so two worlds that spell the same configuration differently still compare equal.