What does error.cause give you when you wrap one error in another?

function loadConfig(text) {
  try {
    return JSON.parse(text);
  } catch (error) {
    throw new Error("Config is not valid JSON", { cause: error });
  }
}
 
try {
  loadConfig("{ broken");
} catch (error) {
  console.log(error.message);
  console.log(error.cause.name);
  console.log(error.cause instanceof SyntaxError);
}
 
console.log("cause" in new Error("plain"));