<conspiracy_hat>
Some of those videos have comments related to Apple's commitment to respecting privacy and/or something to do with ads being bad ; now they want to "go in a different direction" and are doing a 1984.
</conspiracy_hat>
<hat type=conspiracy>...</hat>
Source: HTML Standard Snapshot per today (November 5th 2022):
https://html.spec.whatwg.org/commit-snapshots/53346e4641595a...(using a snapshot here to avoid link rot)
• Name has to start with a lowercase ASCII character. It cannot have an uppercase ASCII character anywhere. UTF-8 characters, emojis, etc. are allowed as long as they are not the starting character
• Name must contain a dash ("-") character. This dash character helps the browser to distinguish custom elements from regular elements.
https://html.spec.whatwg.org/multipage/custom-elements.html#...