This likely stems from the proposers building on existing "in-the-wild" development patterns: it's become a convention for DSLs in the JS development community.

This likely stems from the proposers building on existing "in-the-wild" development patterns: it's become a convention for DSLs in the JS development community. Consider similar for a larger amount of data: <script type="custom-dsl">{ "very": { "large": "json", "object": "with", "many": "keys" }</script> Even sticking strictly to JSON (the DSL can be any syntax), this has a few advantages to SGML-style attributes: 1. Supports nesting to any depth 2. Easier to deserialize from an in-memory object in the most common server-side languages 3. Supports easy developer/hacker copypasta into a JS file for debugging. 4. Broader/better expand/collapse support in text editors (in the case of very large lists) --- > I'd have to look up every time I wanted to use it I'd likely have to look up the HTML attribute names just as much - I recall having to do this a lot at first with the viewport meta when it was introduced - the only real hurdle to get over with this is to internalise the following pattern (which, as mentioned, some in the JS community are already familiar with): <script type="dsl-name">DSL SOURCE</script>