MVG STEP viewer uses unmodified occt-import-js 0.0.23 by Viktor Kovacs and Open CASCADE Technology. LGPL-2.1 license texts are provided alongside these separate, replaceable library files. Wrapper source and build instructions: occt-import-js-0.0.23-source.tgz. Upstream source: https://github.com/kovacsv/occt-import-js/tree/c2148e54b456b571238d35cac037d304053d64b2 . Complete Open CASCADE source at submodule commit d2abb6d844231cb8f29be6894440874a4700e4a5: occt-d2abb6d-source.tar.gz (served alongside this notice). Unpack the wrapper archive, unpack OCCT into its occt directory, then follow the included CMakeLists.txt and tools/build_wasm_win.bat/README build instructions. No restriction on debugging modifications to these libraries is imposed by the viewer.