Trace those RFCs all the way back. Where does the format originate? Nearly 50 years ago, as a codification of what humans <i>were writing by hand</i>.<p>Those formats make tons of sense where you are encoding messages by hand. Be flexible. Allow comments. Allow continuing headers across multiple lines then turning the extra spaces into one. All this is great when ed (or nothing?) was your mail client.<p>It makes absolutely zero sense in any protocol of the last 30 years at least. Code reuse for parsing a line? No one does that, and supposedly it&#x27;s so easy they wouldn&#x27;t need too, right? And it wouldn&#x27;t work anyways, as different headers have different rules - you can&#x27;t treat it just as a sequence of name-value pairs.<p>Extensibility has nothing to do with text vs binary. And my complaint is bad text formats. Having strict, simple, rules, then using ASCII printable chars is just inefficient, but not atrocious.<p>HTML is funny example, being the poster child of crap-interop, with browsers interpreting things differently, even at a basic level (unclosed tags, incorrectly closed tags, spacing, etc.).<p>Can you explain how text is more extensible? Seems like that&#x27;s totally dependent on the spec.