Interesting. On their faqthey claim differently. Or they try to make it seem that they claim differently.
Is collecting the install data GDPR and CCPA compliant?
The method we are using to calculate installs is currently derived from aggregated data from various sources collected in compliance with all privacy laws and used to build a confidence around our estimate. If anything changes, we will provide you with notice and compliance mechanisms to assure all parties remain in compliance with applicable laws. Please note we will always work with our customers to ensure accurate billing.
What various sources were used to estimate that your tester used the game?
Will games made with Unity phone-home to track installs?
We will refine how we collect install data over time with a goal of accurately understanding the number of times the Unity runtime is distributed. Any install data will be collected in accordance with our Privacy Policy and applicable privacy laws.
So actually, they do not have the slightest clue how to collect the data, and hope they will come up with something that does not get them sued over breaking privacy laws. And this one will be tough. Will players have to agree to tos and eula of Unity now, for playing games made in Unity? Retroactivly? Because all this applies to already made games as well.