[flohofwoe]

You can get a simple WebGL2 WASM app down to a couple of kBytes, for instance this downloads 30 KBytes in Chrome:

https://floooh.github.io/sokol-html5/clear-sapp.html

(1.4 KB for the .html, 8.8 KB for the .js, 14.5 KB for the .wasm - and a whopping 5.5 KB for the 404 page returned by Github pages for the missing favicon - wtf...)

The .js file is basically glue code between the WASM code and the browser runtime environment.

Without the Emscripten "convenience runtime" you can also go smaller, but at a few dozen KBytes more or less it's pretty deep in diminishing returns territory.

The C library is provided via MUSL these days (in Emscripten). But there's a small 'syscall layer' which is implemented in Javascript (basically if you want to run in the browser and access web APIs, at some point you need to go through Javascript).