In this case they seem to be firmly closing the path though

> There will not be a separate process for submitting patches by other means. We do not want to create a shadow contribution system through issues, comments, email, or forks. External code can of course exist under the terms of the license, but we will not treat forks or patch dumps as a review queue for upstream Ladybird.

This does raise the question on how they are going to get new maintainers. The only thing I can think of is by active outreach to people contributing to adjacent projects that are still open. But that does not seem ideal to me as that will not yield people specifically interested and caring for the project you invite them to.