Cargo Features

[dependencies]
scan_fmt = { version = "0.2.6", default-features = false, features = ["std", "regex"] }
default = regex, std

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

std default

Features from optional dependencies

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

regex default