Comment 5 for bug 2060817

It comes from /etc/os-release

Ubuntu Pro definitely applies to flavors.

gnome-initial-setup dropping gnome-online-accounts was an upstream decision. By using the default web browser instead of a webkitgtk popup, it fixed lots of existing bugs and future bugs when Google or Microsoft change their protocols.

https://launchpad.net/ubuntu/+source/gnome-online-accounts/3.49.0-1
https://discourse.gnome.org/t/removing-online-accounts-from-initial-setup-46/18624

That particular detail happened to land in noble release before the time_t transition began
https://launchpad.net/ubuntu/+source/gnome-initial-setup/46~alpha-2ubuntu1