Describes the cause and action for error messages.
Error Message(English)：
cannot delete branch
Deleting a local branch with Git - Stack Overflow
https://stackoverflow.com/questions/41492254/deleting-a-local-branch-with-git
Git: Delete the branch only if there is no warning
https://stackoverflow.com/questions/49942482/git-delete-the-branch-only-if-there-is-no-warning
How to delete local empty git branch
https://stackoverflow.com/questions/49609790/how-to-delete-local-empty-git-branch
Delete a local development branch
https://stackoverflow.com/questions/47216073/delete-a-local-development-branch
How to delete a git working tree branch when its working ...
https://stackoverflow.com/questions/44109234/how-to-delete-a-git-working-tree-branch-when-its-workin・・・
GitHubでのブランチの削除 - Qiita
https://qiita.com/keisuke-mizoguchi/items/6e25dedd53b439ef3dad
[Git]ブランチを削除する
http://www.curict.com/software/Git/git_branch_remove.html
git - Can't delete branch SourceTree - Super User
https://superuser.com/questions/1277558/cant-delete-branch-sourcetree
Cannot delete branch protection when branch is deleted - GitHub
https://github.com/go-gitea/gitea/issues/5922