What we're discussing are not custom elements. If you rename a div into <some-other-name>, it doesn't make that a custom element.
Very quite literally in the very literal sense of the word the only way to create actual custom elements is through javascript. There's no other way.
A sibling comment posted this link: https://codepen.io/dkoch-org/pen/yLwPVYG. And this is not custom elements. These are "elements unknown to the browser which will be treated in a neutral way making them indistinguishable from divs/spans". In the context of "preventing div/span soup" this does absolutely nothing. It's the same soup, just with longer names.
Defining them in js doesn't "do anything" either. I think the dispute here boils down to why you would prefer longer names over div/span everywhere. It doesn't make any difference to users, but can make it a lot easier for developers. That's the main reason to do it for me.
Very quite literally in the very literal sense of the word the only way to create actual custom elements is through javascript. There's no other way.
A sibling comment posted this link: https://codepen.io/dkoch-org/pen/yLwPVYG. And this is not custom elements. These are "elements unknown to the browser which will be treated in a neutral way making them indistinguishable from divs/spans". In the context of "preventing div/span soup" this does absolutely nothing. It's the same soup, just with longer names.