Cargo Features

anychain-core = { version = "0.1.3", default-features = false, features = ["std"] }
default = std

The std feature is set by default whenever anychain-core is added without default-features = false somewhere in the dependency tree.

std default = base58

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features.

base58 std