Updates to SharePoint List Templates

There was a recent post in the Message Center of my tenant about the updating of SharePoint List templates. The link provided in message was a how to turn on classic and modern experiences on libraries and lists. It would be nice to know what will exactly be changing, what new elements will be added. I checked the roadmap and poked around the techcommunity, had no luck. Chris McNulty do you have any resources that can be shared?