https://dataoptout-ui-prd.uca.cloud.unity3d.com/?token=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Seems they had data on my token from the game. Meaning they collect data to sell...
Wow, this needs to be looked at ASAP and removed for GoG version.

https://i.postimg.cc/fW5SG4B9/iron.png


(here's the unity page)
https://i.postimg.cc/vmR4rGHp/image.png

That's nothing new. Unity even mention it very clearly in their FAQ (check "I play a game built with Unity software, what should I know?"):

https://unity3d.com/legal/privacy-policy

That's one of the reasons I start all Unity-build games in a sandbox without network access.

Yep, just the usual stuff all games with newer builds of the Unity Engine pull off.
The Devs can't even turn it off as far as I know.

I just use my firewall to block any access to the Google Cloud IPs the game wants to contact. And at last Iron Harvest does not CTD when you do so.

How do you know if the game is collecting data?

At first if a game tries connect to any other IP then the usual 127.0.0.1 (or something else of the internal IP-Range) something is fishy, when we do talk about the GoG offline installers.
It might be the MP-Server but the game should work without reaching that one, when wie talk about an SP-title.

About the special case Unity engine.
Unity says, that they are collecting data and devs said, that they can't deactivate the basic datamining of the unity engine at all. They just can opt in or opt out for aditional datamining.