Cargo Features

[dependencies]
pem = { version = "3.0.4", default-features = false, features = ["std", "serde"] }
default = std

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

std default

Enables std of base64 and optional serde

serde:

Provide impls for common standard library types like Vec<T> and HashMap<K, V>.
Requires a dependency on the Rust standard library.

serde

Enables serde

Pem has 3 features without comments.