My understanding is that Zig's incremental compilation will work on a much more granular level (i.e. functions, etc), so, for example, change one function and only that function (and its dependencies) will get recompiled/relinked (there's some linker trickery involved to avoid needing to relink everything IIUC).
More details here: https://ziggit.dev/t/how-zig-incremental-compilation-is-impl...