Cargo Features

[dependencies]
winterfell = { version = "0.8.3", default-features = false, features = ["std", "concurrent"] }
default = std

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

std default concurrent?

Enables std of winter-prover and winter-verifier

concurrent = std

Enables concurrent of winter-prover

Winterfell has 3 features without comments.