Cargo Features

[dependencies]
bar-config = { version = "0.2.1", default-features = false, features = ["json-fmt", "toml-fmt", "serde_yaml"] }
default = serde_yaml

The serde_yaml feature is set by default whenever bar-config is added without default-features = false somewhere in the dependency tree.

json-fmt = serde_json
toml-fmt = toml

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_yaml default

Enables serde_yaml ^0.8.1

serde_json json-fmt?
toml toml-fmt?

Enables toml ^0.4.6