A comma-separated list of names of packages which the build system will consider non-existent, even if they are visible somewhere on the package path.Use this option when deleting a subpackage 'x/y' of an existing package 'x'. For example, after deleting x/y/BUILD in your client, the build system may complain if it encounters a label '//x:y/z' if that is still provided by another package_path entry. Specifying --deleted_packages x/y avoids this problem.