Cargo Features

[dependencies]
openthread-sys = { version = "0.1.4", default-features = false, features = ["ftd", "mtd", "go-faster"] }
default = cli, ftd

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

cli ftd default
mtd
go-faster

A feature with no dependencies is used mainly for conditional compilation, like #[cfg(feature = "go-faster")].