Cargo Features

[dependencies]
scl3300 = { version = "0.5.0", default-features = false, features = ["libm"] }
default = libm

The libm feature is set by default whenever scl3300 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.

libm default