Unfortunately, even though Tobii provides the SDK and returns some basic data about the tracker, any additional information, such as the gaze data, is unavailable unless you purchase one of their supported eye trackers.

And if you plan to capture/store any of the gaze data, you'd have to agree to their separate license.

If you're wondering, the scenario is the same with the other SDKs they offer, such as the Python one. Even though their forums have been wiped, you can still find conversations on this matter via the Wayback Machine dating back to 2020.