To show you can push to ndom91/briefkasten, add a file named .favz-claim at the top
of its default branch, holding this line:
favz-claim-1790841880-6f296e12d89a4840187f5c90
Then press Check. A pull request works too, once someone who can push merges it.
The code works for 7 days; keep this page or come back with the same link and a new code. We read the file once through GitHub's public API and keep the repo, the GitHub login of whoever committed the file, and the date. Delete the file after. You don't need to claim a repo to get it off Favz: ask for removal, no proof needed.