Why my 20.04.1 offers me Pop!_OS 20.10 upgrade?

One day I logged into my system and it started offering me “Pop!_OS 20.10 is available.” popup. The system is “Ubuntu 20.04.1 LTS” and was upgraded from 18.04 TLS release via standard Ubuntu upgrade.

Why am I getting this Pop distro upgrade? Is something wrong? I know that Pop distro is not Ubuntu and never have been. And I also can’t find any information about this strange upgrade. Is this some kind of a virus or what?

Upgrade screenshot
Ubuntu about page