This past week, I setup a custom binary format on my workstation for WebAssembly. Such formats can be setup without modifying the kernel thru the binfmt_misc capability built into the Linux kernel. This allows specifying an interpreter for files that are neither a native binary format nor a script starting with #!. In my case, I setup an interpreter for WebAssembly using the wasmtime runtime. To do so, I created a file at /etc/binfmt.