Constant MAX_OUTPUT_CAPTURE_LIMIT 

pub const MAX_OUTPUT_CAPTURE_LIMIT: usize = _; // 67_108_864usize

The largest capture_limit an executor accepts.

The capture buffer is resident for a child’s whole life and there is one per stream, so a study evaluating p trials at once holds up to 2 * p * capture_limit bytes of child output. 64 MiB is 1024x the 64-KiB default — which is itself already far past the single last line the result protocol reads — and matches the ceiling the facade’s remote protocol puts on one frame, so the two per-connection and per-child bounds cannot be configured out of proportion with each other. A request for more is a configuration mistake, not a workload.