The feature, only available for Labs users in the US in English, lets you generate «quick, conversational audio overviews» for «certain» search queries.
That should let the audio play for you while you are multitasking or turning attention elsewhere.
«It gives a lay of the land», Google says, and The Verge notes it can also be set to a feature known to many NotebookLM users — with two simulated «podcast hosts» enthusiastically debating the results for you.
You can opt into the feature on Google Labs, and the feature will then pop up as an alternative under Google’s AI overviews on the results page.
Read more: Google’s blog announcement, and a summary at The Verge