It's explained in replies to the tweet, Google apparently lets you specify a "display URL", that's updated immediately but only verified within 24h for trusted accounts. (https://eligrey.com/blog/link-fraud/)

Ah thank you! Replies are not visible without a Twitter account so I didn't see that.

Seems like an absolutely terrible idea.

fyi you can modify the URL to xcancel.com to view replies

I think this came up before in the context of scammy Google ads. Apparently you can set any vanity URL you like to be displayed, which indeed seems like the perfect invitation for scammers if it works without any restrictions.

Presumably it's so you see the nice destination URL, and not the link tracking URL.

The intent is clear, yes. But given how well-known this problem is by now, I would expect a company of the size of Google to have a practical solution to combat this sort of scam, e.g. requiring that the vanity URL points to page containing a specific advertiser ID in the HTML source, or that the canonical URL of the URL with tracking parameters points to the vanity URL, etc...

There's so many solutions to this problem that allow vanity URLs to continue to work. Google just doesn't care.

Yeah, agreed. Or even that the advertiser has a subdomain of the target, like set your DNS of stats.brew.sh (I know they weren't actually buying ads, but just as an example) to be an IP of the tracking system, and then you can just verify the domain names match again.

Yes! This is working as intended, because it earns more money.