Thanks! The file sharing is part of the base, FOSS Tela. It uses WebDAV rather than FUSE. The tela client runs a local WebDAV server that proxies file operations through the WireGuard tunnel to the agent on the remote machine. You can mount it as a network drive (Windows maps it as a drive letter, Linux/macOS mount it as a directory) or access it via TelaVisor or the tela CLI. It can be configured as read-only or read-write. Certain file extensions can be banned from upload or rename.
I went with WebDAV because it works on all three platforms without a kernel module or extra driver. For my use case (browsing files, grabbing configs, etc.) it works well enough.
Bi-directional sync is an interesting idea. Right now the sharing is one-directional (the agent exposes a directory, the client mounts it), but I could see adding something like that as a layer on top.