Google has been doing the refine by feature since 2017, or at least testing it since then. But now Google is testing a more detailed and layered version of refine by in their search results.
Eric Hedekar from Moz shared a screen shot with me of the new format on Twitter. Before I share that version with you, let's look at the current version, which is a carousel.
Current Refine By Carousel:
Compare that to this test, where Google is showing the ability to refine by month and refine by additional topic layers.
Layered Refined By Feature:
Eric wrote "Looks like the topic layer is getting added to more features," indeed!
Forum discussion at Twitter.