It sounds like all public contribution will simply be impossible. That said, they will continue to develop out in the open on GitHub and you can clone the repo and build whenever you want. You can continue to contribute in other ways.

https://ladybird.org/#contribute

I hate this change and agree with your PR comment. This change makes me sad as well.

My hope is that public contributions can resume in the future. Part of their justification for this step is that they are trying to stabalize the project to produce a stable public alpha. Fair enough. And many Open Source projects have begun to voice concerns over the burden that the massive increase in contributions is causing, often from AI. Linus Torvalds has certainly been flagging this. The Open Source world in general is going to have to navigate this and come to a solution that works without the entire Open Source ecosystem becoming read only.

Once Ladybird ships a "stable" browser out to the world, I am hoping they can adopt whatever the "best practice" for Open Source has become to be able to accept public participation again.