No, it doesn't. You have like a "big" switch between the target architectures (WebGL and "PC") and then within "PC" (which more or less has the same CPU code with them all being x86 architecture (more or less now that Apple added M1 ARM chips into the mix), but different low level layer for the runtime.
Therefore, for a typical jam game there would be 4 versions to build, one WebGL for browser playing and one of each, Linux, Mac, and Windows.