The Magento 2 extension allows a merchant to be able to leverage Amazon’s 20+ years of machine learning systems, and use their algorithms to power a Magento store’s product recommendations. All data is self-contained and is not commingled with Amazon in any other way. Personalized Product Recommendations for users.
The module license OSL 3.0 states that it is free open source, but in magento admin I'm asked to enter a license key?