Function check_required_env 

pub fn check_required_env(
    name: &str,
    version: &str,
    description: &Description,
    env_allow: &[String],
) -> Result<(), RuntimeError>

Checks that every variable description.required_env names is declared in capabilities.env.allow, given as env_allow. Names match exactly.

The refusal lists every undeclared name, in the driver’s order, each once.