Cargo Features

[dependencies]
ip2location-iso3166-2 = { version = "0.4.0", default-features = false, features = ["once_cell"] }
default = once_cell

The once_cell feature is set by default whenever ip2location-iso3166-2 is added without default-features = false somewhere in the dependency tree.

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.

once_cell default

Affects csv_format::RECORDS, csv_format::RECORDS_CODE_MAP