<idea-plugin version="2">
  <project-components>
      <component>
          <implementation-class><error descr="Cannot resolve class or package 'foo'">foo</error>.<error descr="Cannot resolve class 'Bar'">Bar</error></implementation-class>
          <skipForDefaultProject/>
          <loadForDefaultProject/>
          <<error descr="Element unknown is not allowed here">unknown</error>/>
      </component>
  </project-components>
</idea-plugin>