It's available as a podcast here: https://data.voxsnap.com/podcast/ycombinator.rss

Yep. Use Chrome Dev Tools, Network tab you can see each mp3 as it is opened and downloaded. Here's the intro: https://storytime.voxsnap.com/30/audio/2018/09/14/ycombinato...

Either iterate through each section guessing the URL or give dev tools a go.

EDIT: See my comment here for all of the mp3s: https://news.ycombinator.com/item?id=18917784