However, there are that can run on PC hardware via ISO-like images:
It sounds like you're asking for a of Firefox OS — specifically whether it's available as an ISO file (i.e., for installation on a PC or as a bootable live system). firefox os iso
Community-maintained snapshots can be found on sites like the Internet Archive , though these are versions of the "Boot to Gecko" builds rather than modern bootable ISOs. Successors and Modern Alternatives However, there are that can run on PC
These are executable versions of the OS that run as a windowed application on Windows, macOS, or Linux, allowing for testing without a full OS install. firefox os iso