Ubuntu has this package installed by default:
network-manager-config-connectivity-ubuntu

It's only purpose is to provide settings for NetworkManager to send requests to connectivity-check.ubuntu.com , and based on the result (AFAIK) detect redirection by captive portals and open an ISP's page (think public WiFi, or hotel rooms, where you need to authorize to access the net).

Well, connectivity-check.ubuntu.com is hosted on Google cloud (you can check that by running:

dig connectivity-check.ubuntu.com
whois [the IP from previous query]

), so by default Ubuntu sends requests to a Google cloud page.
I don't say Google counts daily active Ubuntu users (because many of those have the same IP), or that Google actively logs and analyzes that data. But some of you guys may not like that behavior.

So what's the fix?

Purge the package

sudo apt purge network-manager-config-connectivity-ubuntu

If you do need a captive portal detection, create your own config file to query some HTTP (not HTTPS) page of your choice, in the example below I have a Debian page used for the same purpose. Use your favorite text editor to create and edit /etc/NetworkManager/conf.d/90-connectivity-custom.conf :

[connectivity]
uri=http://network-test.debian.org/nm

Restart NetworkManager

sudo systemctl restart NetworkManager

If you run an Ubuntu derivative, please report if you have network-manager-config-connectivity-ubuntu installed in the comments.