No. It was a separate project attempting to provide a SteamOS Holo-style installation for generic hardware.
HoloISO vs SteamOS: why project maintenance comes first
HoloISO was an attempt to make the Steam Deck-style SteamOS Holo experience installable on generic hardware. That historical goal explains why it still appears in comparison searches. Its current public status matters more: the HoloISO GitHub organization is marked EOL. That makes it a poor default recommendation for a new gaming setup.
To place this tradeoff among the available distributions, compare SteamOS Alternatives.
SteamOS has a current official path
When this affects the next part of the task, use SteamOS on PC to keep the check specific.
Valve documents supported devices and recovery
Valve currently supports SteamOS on Steam Deck and Legion Go S and publishes installation and recovery guidance. Hardware support may be narrow, but the project has a defined owner.
Use SteamOS where it is actually supported
If you own supported hardware, the official image and support path are safer than recreating an older approximation of the same experience.
HoloISO is not a maintained alternative
EOL changes the decision
End-of-life status means you should not assume current updates, driver fixes, security maintenance, or recovery guidance. An old installation guide can still exist while the project behind it no longer has current ownership.
Do not confuse a close interface with support
A SteamOS-like interface does not provide Valve hardware support, SteamOS update behavior, or a maintained driver path. Those are separate things.
Choose a maintained route instead
Use SteamOS on official hardware
SteamOS is the direct choice when your device has current official support.
Evaluate active alternatives by their own docs
For other hardware, consider a maintained distribution with current hardware and installation documentation, such as Bazzite or ChimeraOS where their requirements fit. Test recovery before committing.