Google seems to be returning ratings to location extensions of AdWords ads in the Google search results.  They originally launched last year, but then vanished from use.

Here is what it looks like:

But when you view it as part of the page, the ads with location ratings really stand out, especially if none of the other results have any ratings at all displayed.

This could possibly be back as a test phase, instead of permanently returning.  This is something that Google began showing in 2015 before they were removed.   Subsequent searches for this did not always return the ratings, even when the same ad appeared.  And I couldn’t find other examples for the same feature.  It could possibly be in a rolling out phase, if it isn’t just a test.

Here is the same ad again, with the location extension but without the ratings showing:

These ads are taken from Google My Business ratings, so a business would need to have great ratings in GMB in order to show ratings via location extension.

If you have these still set up from 2015, Google might possibly begin showing them again in your AdWords ads automatically.  Otherwise, you should contact your AdWords rep for more information about them and to set them up.