Cargo Features

zzz = { version = "0.3.1", default-features = false, features = ["auto-width", "streams"] }
default = auto-width

The auto-width feature is set by default whenever zzz is added without default-features = false somewhere in the dependency tree.

auto-width default = term_size
streams = futures-core

Affects zzz::streams

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features.

term_size auto-width
futures-core streams?

With default (std)