What sorts of sites are you thinking of? To me, “most useful to a programmer” evokes docs and blogs and github issues and forum posts. I suppose some forums might be AI-resistant (login wall), but the others are trivially AI accessible.
GitHub is naturally LLM resistant via its new uptime feature… I’ll show myself out.
Plenty of Linux-y websites use Anubis. Arch Wiki and IIRC some other distros too.