WooCommerce Google Product Review Feed GPL Overview:

Display star ratings below your Google Shopping Ads and boost shopper confidence and help increase the click-through rate on your ads. This extension generates a product review feed URL that you can submit through the Google Merchant Center. Your reviews will be matched up with your products in Google Shopping and the ratings will appear below your shopping ads.

The extension does the following:

1. Generates an XML review feed that Google will fetch on a scheduled basis.
2. Gives you the ability to choose the unique product identifier (GTIN) to include in the review feed.
3. Gives you control over which product reviews to include in the feed.