Cargo Features

[dependencies]
c-ares-sys = { version = "10.1.0", default-features = false, features = ["maybe-vendored", "vendored", "build-cmake"] }
default = maybe-vendored

The maybe-vendored feature is set by default whenever c-ares-sys is added without default-features = false somewhere in the dependency tree.

maybe-vendored default vendored?
vendored = maybe-vendored
build-cmake = cmake

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.

cmake build build-cmake?