I am using OnePlus 3T, Android 9. Recently I installed an app called "NoRoot Firewall" to prevent the apps from accessing the internet. I explicitly allowed and denied access to internet for some apps but didn't allow or deny the "System" (default) app to access the internet. If you don't allow or deny the the access, it will send you a notification when that app tries to access the internet.
I started receiving notifications when the "System" app tried to access the internet on multiple occassions. I ignored it for a week and I didn't see any issues in my phone as such. I was expecting if the system doesn't get internet, it will fail the operation that it was trying to do and I would notice it if I use that feature but I didn't notice any change.
Here is a screenshot of the URLs/IPs that it tries to access.
I tried hitting those URLs/IPs in my browser to check the certificate but it says it's missing certificate even though in the URL it shows that it's trying to access it on port 443.
Please provide your thoughts.