Isn't this valid? This comes from the [`wp` Bash command](https://github.com/wp-cli/wp-cli/blob/master/bin/wp#L46):

```bash
exec "$php" $WP_CLI_PHP_ARGS "$SCRIPT_PATH" "$@"
```

And [`boot-fs.php`](https://github.com/wp-cli/wp-cli/blob/master/php/boot-fs.php) is what fires up WP-CLI.