Cargo Features

[dependencies]
sp-block-builder = { version = "34.0.0", default-features = false, features = ["std"] }
default = std

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

std default

Enables std of sp-api, sp-inherents, and sp-runtime

sp-block-builder has 2 features without comments.