Open letter here: https://openletter.mousetail.nl
I haven't decided what I think about this yet. It seemed fairly apparent months ago that technical support was a prime target for ChatGPT et al., and this is a technical support WWW site.
The question of whether this will affect this WWW site, that I was going to post, has already been answered; as the signatures list on the letter grew as I was writing this question.
So at this point this is more of a public service announcement than a question.
There's a whole lot more at Sustainability of new AI generated content policy and a fair number of other meta places, too, for the curious.