code: @Override
  	protected Set<OutputConfiguration> getOutputConfigurations(IProject project) {
  		final Set<OutputConfiguration> original = this.configurationProvider.getOutputConfigurations(getProject());
  		return Sets.filter(original, it -> !ExtraLanguageOutputConfigurations.isExtraLanguageOutputConfiguration(it.getName()));
  	}
docs: Replies the output configurations for the given project.
  
  <p>This function filters the output configurations in order to never reply one
  associated to a extra language output.
  
  @param project the project.
  @return the output configurations associated to the given project.