Cargo Features

sid2 = { version = "0.4.0", default-features = false, features = ["sqlx", "rand", "serde"] }
default = rand

The rand feature is set by default whenever sid2 is added without default-features = false somewhere in the dependency tree.

sqlx = uuid

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features.

rand default

With default features

uuid sqlx?

With default (std)

serde implicit feature

With default (std)