Strange E-Mail - scam?

Remarkably unsuccessful then since it leads nowhere

Yes, I know what an IDN is, I mentioned it earlier, but please look at the source of the first message in this thread and tell me, do you see the punycode in there?

No I won't! It's ordinary text in a terminal window, hovering a mouse cursor over it does nothing as there's nothing to do.

That's what I've been trying to tell people. Thunderbird is f****ng up and fooling everyone.

It sees the mangled "smart" quotes ’ immediately following the .uk and *incorrectly* assumes this an attempt to sneak illegal characters into the URL, so "fixes" this, but in reality it is making matters worse ...

Reminding you to tax a vehicle that you previously owned or scrapped?

No, although I do see UTF-8 apostrophes (e28098 and 99) in the first occurance.

(Going into my newsfeed cache on disc to try and avoid any interference from my newsreader (emacs/gnus)).

$ grep http 1313319 | xxd

And here is what's going on ... mangled characters like those "smart" quotes is a common encoding issue with C&P'ed text, but in this case that error gets compounded.

Thunderbird knows that only ASCII is allowed in a domain name, but because the trailing smart quote (U+2019) immediately follows the .uk it sees that as an attempt to smuggle anillegal domain, and tries to punyencode the TLD uk’ resulting in xn--uk-o2t when you hover, it then shows the "fixed" URL

Treat it as a scam.

xn-- is the Punycode identifier, xn--uk-o2t is the Punycode for 'uk' (0x75, 0x6B in UTF-8) followed by U+2019 RIGHT SINGLE QUOTATION MARK.

ie Thunderbird has decided the closing quote mark is part of the URL and generated a Punycode-encoded version including the quote.

Theo

Indeed, if you go to CyberChef:

www.gov.xn--uk-o2t

is a way of representing: