A month ago, Overwolf, SteelSeries and Tobii announced the Sentry development Challenge 2014. The challenge is currently in progress so it is too late to sign up. However, you can still use the Overwolf SDK if you want to use your Tobii EyeX compatible eye tracker to build game overlay apps with Tobii EyeX functionality.
If you want to discuss the Tobii EyeX API available in Overwolf, you are welcome to use the forums. You may also contact firstname.lastname@example.org for more support related issues regarding the Overwolf integration.