From the documentation:

RetroArch Cloud Sync is available in recent RetroArch Nighties and enables a seamless synchronization of the most important system configuration and save data to a dedicated private webdav server, from where these data can be synchronized across Apple devices. The current functionality is limited to Apple devices (MacOS, iOS, tvOS) because it was developed here. It can be deployed to other RetroArch operating systems, if a developer is interested in this work.

This is pretty rad. I just set it up on my iPhone and plan to do so on our Apple TVs later today. It’ll be nice to have all of my saves synced between devices so I can pick up and play from where I left off regardless of the device I’m using.

➝ Source: docs.libretro.com