Cargo Features

[dependencies]
stackvec = { version = "0.2.1", default-features = false, features = ["nightly", "a_thousand_array_impls"] }
default = a_thousand_array_impls

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

nightly
a_thousand_array_impls default

StackVec has 3 features without comments.