Cargo Features

[dependencies]
sid2 = { version = "0.4.1", 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

Enables sqlx ^0.7

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

rand default

Enables rand ^0.8.5

uuid sqlx?
serde implicit feature

Enables serde

serde:

A generic serialization/deserialization framework