Cargo Features

[dependencies]
ckb-hash = { version = "0.120.0-rc2", default-features = false, features = ["ckb-contract", "blake2b-rs"] }
default = blake2b-ref, blake2b-rs

These default features are set whenever ckb-hash is added without default-features = false somewhere in the dependency tree.

ckb-contract = blake2b-ref

This feature is used for CKB contract development

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.

blake2b-ref default ckb-contract?
blake2b-rs not wasm32 default