> Browsers absolutely decode as much as they can, and if the file is corrupted halfway through you generally get garbling, not the entire image being replaced by "fuck off". The only case where that is so is if the browser can't parse anything at all, or can't retrieve the file.

What I meant is that you don't expect PNG or JPEG images to be created in a way that the parser needs to run a complex process to reconstruct the bits that are broken and interpret what you meant to say. Like this one:

https://html.spec.whatwg.org/multipage/parsing.html#adoption...

Perhaps a better example is a C program being compiled into an executable. You don't expect the compiler to guess what you meant while parsing.

The current expectation is that a web browser must load any broken HTML and still display what it can, and is this expectation what I would like to change.

I don't propose humans to write this format directly (although it should be human readable), but compile it from something that is easy to write, like Markdown or a similar language. The objective is to enforce tools that make the transformation to produce a strictly conformant document.

Having a context-free grammar allows simple and fast parsing tools that can process your document, in a similar way that you can query or manipulate a JSON file with tools like jq because the grammar is simple and strict.

> That... is not how anything happened.

What the heck are you talking about? User agent devs and users did indeed always go toward it mostly works.