I couldn't find anything after like a minute of searching. Unless we're counting the gif that slowly shows you an example project letter by letter.
* https://github.com/cuelang/cue/blob/master/doc/tutorial/basi...
* https://github.com/cuelang/cue/blob/master/doc/tutorial/kube...
Edit: Ah, the code example only appears for desktop browsers (or at least, browser windows wider than a phone screen).
And it's one of those trendy shitty live-typing demonstrations instead of just letting you read some text.
So if you add a field, you break existing code that doesn't know about the field.
Even for those that you choose to close, it’s a matter of having different code for different definitions. The claim that it just automatically breaks isn’t true even when closed definitions are used.
BTW, this feature speaks to CUE’s intended purpose as a configuration language. It is (or at least can be) nice to ignore unknown fields in transmitted payloads for forwards and backwards compatibility. But if I’m trying to configure some software and misspell a field, I probably want the configuration file to fail validation, not have the software run with an unintended configuration.
In this case, it is helpful because we can scale our understanding of the poster's disappointment to allow us to not have to consider how it might be disappointing relative to, say, global thermonuclear war or a first kiss, but only need to think about it in relation to the other topics of discussion.
I highly recommend using context whenever communicating.
The most important part of any programming language website is a short example snippet: put it above the fold on the front page!