Cargo Features

[dependencies]
iso13400-2 = { version = "0.1.0-alpha1", default-features = false, features = ["std2010", "std2012", "std2019"] }
default = std2012

The std2012 feature is set by default whenever iso13400-2 is added without default-features = false somewhere in the dependency tree.

std2010
std2012 default
std2019

iso13400-2 has 4 features without comments.