> the browser dev tools already have to include a "prettify" option. Moving to a binary protocol would turn that into "decompile" and make it mandatory, but it effectively already is.

This will be a legal problem. At least in my jurisdiction, transforming source code (which is what prettifying is) is not subject to legal restrictions, but decompiling binary machine code into readable source code is forbidden by copyright law. (For the same reason, I'm concerned about WASM.)