TripoSR.ai uses occt-import-js 0.0.23 to read STEP files locally in the browser.

Project source: https://github.com/kovacsv/occt-import-js/tree/0.0.23
Package: https://www.npmjs.com/package/occt-import-js/v/0.0.23

occt-import-js and Open CASCADE Technology are distributed under the GNU
Lesser General Public License v2.1. Their license texts are provided alongside
this notice as license.occt-import-js.txt and license.occt.txt.

The browser downloads these JavaScript and WebAssembly distribution files only
after a user asks to open a STEP/STP file. The JavaScript loader is reproduced
by scripts/vendor-occt-import-js.mjs from the locked npm package, verifies the
upstream SHA-256 digests, and lowers the WebAssembly maximum-memory ceiling
from 2 GiB to 512 MiB. The WebAssembly binary itself is unmodified.

The public sample /samples/cube-10x10mm.step is copied from the occt-import-js
0.0.23 test suite at test/testfiles/cube-10x10mm/cube-10x10mm.stp and remains
available under the same LGPL-2.1 terms.