Browse and edit files directly on your server over SFTP — no download, no local copy, no sync step. Changes save straight to the remote path.
Remote Filesystem is a toggle on each named remote path, not a global setting. Keep it off for projects where you want the traditional upload/download workflow, and turn it on for servers where you'd rather edit in place — a staging box, a Raspberry Pi, a production config directory you only touch occasionally.

Turn on Remote Filesystem for a server's remote path and the sidebar switches to browsing that server directly over SFTP. Open a file, edit it, save — the change lands on the server immediately. There's no local copy to keep track of.
This is a different model from pushing and pulling a project tree: instead of syncing state between your iPad and the server, you're working on one copy, in one place.
Traditional sync means two copies of your project can disagree — an edit on the server, an edit on your iPad, and now you're merging by hand. Remote Filesystem Mode removes the second copy entirely, so what you see in the editor is exactly what's on disk on the server.
That also means changes made outside Remote IDE — by a deploy script, a teammate, or a process running on the server — show up the moment you reopen the file.