Lack of documentation on --non-interactive

Cannot find any thorough documentation on `--non-interactive`. Only from the command line itself:

> error out of the command instead of waiting for prompts

Are there any assumptions that trigger this option ON automatically?

Do I understand correctly from [command.ts#L211](/firebase/firebase-tools/blob/d86aa5b5f24f1a92529d83c471690be732a4fc07/src/command.ts#L211) that `process.stdin.isTTY` is `false` for Ci environment like GitHub Actions?