Fedora CoreOS nodes are counted by the Fedora infrastructure via the Count Me feature. This system is explicitly designed to make sure that no personally identifiable information is sent from counted systems. It also ensures that the Fedora infrastructure does not collect any personal data. The nickname for this counting mechanism is "Count Me", from the option name. Implementation details of this feature are available in DNF Better Counting change request for Fedora 32. In short, the Count Me mechanism works by telling Fedora servers how old your system is (with a very large approximation).
On Fedora CoreOS nodes, this functionality is implemented in rpm-ostree as a stand-alone method. The new implementation has the same privacy preserving properties as the original DNF implementation.
You can use the following command to disable counting on existing nodes:
$ sudo systemctl mask --now rpm-ostree-countme.timer
You can use the following Butane config to disable counting during provisioning on first boot:
variant: fcos version: 1.4.0 systemd: units: - name: rpm-ostree-countme.timer enabled: false mask: true