Cargo Features

[dependencies]
relevant = { version = "0.4.2", default-features = false, features = ["std", "panic", "serde-1", "log", "backtrace"] }
default = std

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

std default
panic
serde-1 = serde

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.

log implicit feature

Enables log

log:

A lightweight logging facade for Rust

backtrace implicit feature

Enables backtrace

backtrace:

A library to acquire a stack trace (backtrace) at runtime in a Rust program

serde serde-1?