Likely cause: this build is Brotli-compressed, but the web server sent a .br file without the header Content-Encoding: br. The browser then tried to parse compressed bytes as JavaScript / WebAssembly.

Fix on the server (see docs/HOSTING.md):

• *.js.br → Content-Type: application/javascript + Content-Encoding: br
• *.wasm.br → Content-Type: application/wasm + Content-Encoding: br
• *.data.br → Content-Type: application/octet-stream + Content-Encoding: br
• Brotli also requires HTTPS (or localhost). For hosts without header control, ship the gzip build (make web-gzip).