@Nullable
  Path getDockerClientExecutable() {
    String property = getProperty(PropertyNames.DOCKER_CLIENT_EXECUTABLE);
    if (property != null) {
      return Paths.get(property);
    }
    return dockerClient.executable == null ? null : dockerClient.executable.toPath();
  }
Gets the configured extra layer file permissions.

@return the configured extra layer file permissions
jib-maven-plugin/src/main/java/com/google/cloud/tools/jib/maven/JibPluginConfiguration.java