My point is that HTML and CSS rarely is "source code" these days, (i.e. "the preferred form for modification") but the output of a tool. Back when we were using

My point is that HTML and CSS rarely is "source code" these days, (i.e. "the preferred form for modification") but the output of a tool. Back when we were using assemblers instead of compilers, assembly was considered source code, but now it's an opaque object. It is most HTML and CSS these days: opaque objects. If nothing else, the identifiers and CSS selectors can be easily obfuscated.