rev v4
Measured Pruning Damage Depends on the Evaluation Corpus: A Renaming Control for Mixture-of-Experts Expert Pruning
Pruning 32 experts per layer from a 256-expert MoE costs 44% of base NLL on CPython stdlib and 16% on the same files with identifiers renamed: the reported damage figure moves 1.6× in absolute nats under a rewrite that changes no program structure. Flip rates at confidently predicted positions halve. An extractability probe confirms the corpora differ in memorisation as intended, but per-file extractability does not predict per-file damage, so memorisation is reported as the hypothesised mechanism rather than a demonstrated one.