It's always amusing to see DNS "hackery"[1] like this, and always makes me go back to DNS Toys (https://www.dns.toys/), which generated a huge discussion on HN a year ago [2]

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[1] well, it's not really hackery if you're being pedantic, since it's doing what the spec allows it to do

[2] DNS Toys (946 points): https://news.ycombinator.com/item?id=31704789