My mistake. 80k is the debug mode output size. In release-small mode, it is 68k. In other words, Zig 0.17 shrinks the size more 2k.
Zig 0.16 makes #TapirMD wasm library output size shrink to 70k (from about 76k). However, Zig 0.17 makes it grow to 80k.
Still small.

