Cargo Features

captcha = { version = "0.0.9", default-features = false, features = ["audio"] }
default = audio

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

audio default = hound

Affects audio::Audio

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.

hound audio