KML, Keyhole Markup Language, is the file format Google Earth was built around. It's also useful for anyone who wants to hand off a curated map, a trip itinerary, a set of site locations, without making the other person dig through a shared Google Maps list on their phone.
Google Maps' own list-sharing works fine for viewing a list inside Maps, but there's no built-in button to turn that list into a KML file. MapsLinkQuest reads the list's coordinates directly and builds a standard KML document, one placemark per location, named to match what's on the original list.
Open the file in Google Earth (desktop, web, or the mobile app) and every location shows up exactly where it was pinned. It's also a clean starting point if you're building a custom map layer somewhere else that accepts KML.