Cargo Features

[dependencies]
pallet-staking-runtime-api = { version = "19.0.0", default-features = false, features = ["std"] }
default = std

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

std default

Enables std of parity-scale-codec, sp-api, and sp-staking

pallet-staking-runtime-api has 2 features without comments.