The addition of a new report type named ad group details reports was announced on Google+ .
This has been done to expand on the campaign details reports they introduced last month but now they have done this on the ad group level.
According to Google, this will help people find more granular information about the features and settings enabled in each of their ad groups.
People have now access to the details such as the number of sitelinks that are active or disapproved, if they have mobile bid adjustments enabled within their ad group details reports. One can sort, filter and even add additional performance columns to these new reports.
You can access these new reports under the Dimensions tab in the AdWords console.Google AdWords Announces New Ad Group Details Reports!,