in src/settings.rs [84:90]
fn default() -> Self {
// Produce a default value by creating a mock empty environment, and
// then asking envy to deserialize it. Since all settings have a default
// value specified in the struct, this works and keeps everything in sync.
let empty_env: Vec<(String, String)> = Vec::new();
envy::from_iter(empty_env).unwrap()
}