pub const TARGET_CLOSURES: &str;Expand description
2026-09-25: What each kernel target in this binary was compiled from, as
JSON: a map of "hardware/model/quant" to {hash, arch, compiler, flags},
computed by build.rs’s closure_attestation. The benchmark record copies
it (bench_record.rs, with_closure), so a record attests to the binary’s
sources rather than to the working tree.
{} when no compiler ran (the METRALE_SKIP_BUILD stub emits {}) or
when ComputeTarget::compiler_id returned None.