This demonstration site ships first-party code only. Its WebAssembly module is compiled with the Emscripten toolchain but contains no Emscripten runtime or loader. It contains no LibreOffice and no other third-party software.
The WebAssembly module on this site is compiled with
https://emscripten.org/. The module is freestanding: no Emscripten loader or
runtime is served with it.
Emscripten is dual-licensed under the MIT license and the University of Illinois/NCSA Open Source License. Its notice is reproduced in full below for completeness.
Runtime components supplied by LLVM are licensed under Apache-2.0 with the LLVM exception, which removes the attribution requirement for portions embedded into object code by compiling. They are named for completeness rather than obligation.
Written by hand, first-party, with no external dependency — not even a C standard library header. That is deliberate: it means the module you download contains no third-party code requiring attribution beyond the toolchain above.
The page and the hashing module are first-party. Their licensing status is not addressed by this page.