Cargo Features

[dependencies]
fixedbitset = { version = "0.5.7", default-features = false, features = ["std", "serde"] }
default = std

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

std default

Features from optional dependencies

serde implicit feature

Enables serde

serde:

A generic serialization/deserialization framework