I just read Meet Etcher, A Stylish Open-Source USB Image Writer Tool. It talks about downloading an AppImage.
Yes, Linux; the Linux packages are distributed as a .appimage for 32-bit and 64-bit distributions, and should run across all major Linux distributions without any issues. The team currently has no plan to provide a native .deb (or .rpm) installer.
What are AppImages? How do they differ from snaps?