The Jupiter CLI
The Jupiter CLI is the "official" interface to Jupiter. The CLI stands for "command line interface". As opposed to a GUI or "graphical user interface". Most applications you interact with - your browser or your email client on your computer, or YouTube or Instagram on your phone, are GUI ones. CLIs are much simpler tools, but because you need to interact with them via a shell and type commands to get things done, they're mostly used by power-users.
The CLI essentially manages the local storage and applies any change to Notion too.