Cargo Features

crates_io_api has no features set by default.

[dependencies]
crates_io_api = { version = "0.11.0", features = ["rustls"] }
default

These default features are set whenever crates_io_api is added without default-features = false somewhere in the dependency tree.

Enables default-tls of reqwest

reqwest:

Note: this doesn't enable the 'native-tls' feature, which adds specific functionality for it.

rustls

Enables rustls-tls of reqwest

crates_io_api has 2 features without comments.