$ datalad siblings add -d . --name public --url https://github.com/datalad-handbook/midterm_project.git
[INFO] Could not annex-enable public:   Remote public not usable by git-annex; setting annex-ignore
  https://github.com/datalad-handbook/midterm_project.git/config download failed: Not Found
  Remote public not usable by git-annex; setting annex-ignore
  https://github.com/datalad-handbook/midterm_project.git/config download failed: Not Found
enableremote: 1 failed

.: public(-) [https://github.com/datalad-handbook/midterm_project.git (git)]