How will a pull request on GitHub behave if a fork or fork branch is destroyed?

Question

GitHub

It is easy to read in the GitHub help system that a pull request (a request to merge with the original code that is written inside a fork branch) is inextricably linked to the fork branch from which the code comes. For example, each commit that adds code to that branch of the fork also adds to the pull request.

Do any of you know by experience the answers to the following questions:

• How will the pull request behave if the fork is destroyed before the pull request is accepted by the owners of the original (that is, before the code is merged with the original)? It is clear that it will not be possible to replenish the pull request with commits - but will the previous commits included in it also be destroyed?
   
  
• How will the pull request behave if the fork is destroyed after the pull request has been accepted by the owners of the original (that is, after the code has been merged with the original)? Will the authorship and time of the commits be broken, will the hyperlinks that previously led to the commits from the pull request page be broken?
   
  
• What are the answers to the two previous questions in the case when not the entire fork as a whole is destroyed, but only that branch of it, from which the code was received in the pull request?
   
  
• What happens if you commit to this branch (for example, merge new code from the original) after the pull request has been accepted? Will the pull request get cluttered with new commits?
  

I did not find answers to these questions in the Github help, and that's why I turn to the experience of the Habrahabr community for advice.

Answer 1

EMNIP
1. Closes.
2. Commits will not change (they are already upstream), links will return 404.
3. Responses will not change.
4. Cim is right.