A loader wired to totalLevels fast, cache-resident sub-LOD stubs.
A loader whose sub-LODs report NON-resident, so the streaming policy stops after each level and the ladder is climbed over several passes. That is the shape real refinement takes, and it is materially different from a single resident pass — the single-pass climb concatenates exactly once, so it has no previous cumulative and cannot exhibit the abort-path lineage retention that can pin up to a whole redundant copy at depth (#2426). Committing browser runs retain the same depth curve before and after the release; the multi-pass case protects the uncommitted exit, not a settled deep-rung saving. A contract that only ever ran the single-pass shape looked green through that entire bug.
What a per-geometry test file supplies to run the contract.