Cargo Features

[dependencies]
groestlcoinconsensus = { version = "2.20.1-0.5.0", default-features = false, features = ["std", "external-secp"] }
default = std

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

std default
external-secp

groestlcoinconsensus has 3 features without comments.