Cargo Features

crate_crypto_internal_eth_kzg_maybe_rayon has no features set by default.

[dependencies]
crate_crypto_internal_eth_kzg_maybe_rayon = { version = "0.5.2", features = ["multithreaded"] }
multithreaded = rayon

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

rayon multithreaded?