HTML is valid markdown. So I'm not sure how you make oppose markdown and XML. XML is basically a subset of markdown.

    <b>This</b> <i>is</i> *valid*
    <ul>
    <li>*Mark*</li>
    <li>_down_</li>
    </ul>

Markdown basically adds a whole layer of complexity upon HTML.

▲ Arainach 3 hours ago | parent [-]

If you're writing things like that in Markdown files (without being escaped in code blocks as HTML syntax examples), you're doing it wrong.

Not wrong, perhaps a little weird. HTML is a first class citizen in the commonmark (spec)[https://spec.commonmark.org/0.31.2/#html-blocks].

	▲	Arainach 3 hours ago \| parent [-]
		"Wrong" does not necessarily mean "against the standard". It means "against common usage and good team practice" in this context. It's "allowed" to use raw pointers, malloc, and any number of things in C++ code. In general, if you do any of them in a modern codebase you're doing it wrong.