Cargo Features

[dependencies]
penny = { version = "0.2.0", default-features = false, features = ["std", "serde-serialize"] }
default = serde-serialize, std

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

std default
serde-serialize default = serde, serde_derive

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.

serde serde-serialize
serde_derive serde-serialize