code: public boolean deleteBlobAcl(String bucketName, String blobName, long blobGeneration) {
      // [START deleteBlobAcl]
      BlobId blobId = BlobId.of(bucketName, blobName, blobGeneration);
      boolean deleted = storage.deleteAcl(blobId, User.ofAllAuthenticatedUsers());
      if (deleted) {
        // the acl entry was deleted
      } else {
        // the acl entry was not found
      }
      // [END deleteBlobAcl]
      return deleted;
    }
docs: [VARIABLE 42]