Constant DEFAULT_BUDGET_TRIALS 

pub const DEFAULT_BUDGET_TRIALS: u64 = 100;

The trial budget an Adapter assumes when the caller does not say.

kurobako never transmits its budget to a solver — the protocol has no field for it, because kurobako simply stops calling ask when the study is over. Only SamplerKind::Auto cares (its rule ladder is budget-dependent), so the number is a declaration the benchmark recipe has to keep in step with its own --budget, not something that can be discovered. 100 is a middling benchmark budget: comfortably past the 8-trial floor below which auto prefers a space-filling design.