Underlying announcement might be a better link:

https://godotengine.org/article/contribution-policy-2026/

I predict this won't last long in any extreme version in any significant open source repo.

Banning AI-slop is one thing, but AI as a properly used co-programmer is becoming more and more capable and shutting out well-guided AI will enable competitors who don't to edge and then power ahead.

There are obviously problems to solve here, but blanket bans (while understandable in under-resourced maintenance environments) aren't anything more than a short-term buffer.

Competitors … in open source?

I predict any project that allows AI will slowly degrade in quality

Then those 'competitors' can fork Godot and make their own AI version of it. Will they? No, no they wont. But they sure will complain about the rules while doing nothing about it.