You’ll need to forget that word because it was deprecated many months ago. hassio was the name of a combination of custom operating system Home Assistant as a docker container, and a few other docker containers including one called Supervisor to manage the system. It was installed as a disk-image and available for specific hardware platforms (notably Raspberry Pi and Intel NUC). It is currently known as Home Assistant OS.
What you appear to have is currently known as Home Assistant Supervised. It has everything I described above, except the custom operating system. It is designed to run on Debian. However, it can run on other distros but then it is not considered to be “officially supported” (supported exclusively by the user-community). You should know that even if you use Debian, the machine is supposed to be dedicated to Home Assistant and for no other purpose. If you run other things on it, the development team deems it to be unsupported.
In practice, many people use Home Assistant Supervised on, for example, Ubuntu, with other services/containers, and it works well.
For more information about the four ways you can install Home Assistant, see this post: