Original author of smoltcp here! I couldn't have imagined how much of a cornerstone of the Rust ecosystem it would become. Very excited to see it get used like this, and yeah, #![no_std] use cases were the original and primary motivation to build the stack in the first place.
It uses completely different software (that I wrote together with a small team of volunteers: https://codeberg.org/git-pages/git-pages) which scales very well horizontally and works more like GitHub Pages than Codeberg Pages technically, but in concept you are basically correct.
122 MB of it is Wasm machine code of a MinSizeRel LTO build of LLVM; it is compressed to 23 MB by Zstandard when your HTTP client supports that. That is about as small as you can get an LLVM/Clang/LLD bundle to be, and I put a lot of effort into making it smaller.
248 MB of it is an OpenBSD sysroot; it is compressed to 45 MB by Zstandard when your HTTP client supports that. I have not used OpenBSD and have no particular insight into what's inside.