The package name. Make sure your package name is uniqued, it relate to many things in package programming.
The version number, we highly recommend you use semver standards for your version.
Describe your package in one sentence.
Package entry point. Usually we set this to "main.js". But you are free to set any path relate to your package, such as
Main menu registry. The key is the menu path of your menu item. The value is the menu options. More details check main-menu reference.
The menu path is a posix format path. For instance: "My Package/Preview/Foo Bar" will search the menu in "My Package" > "Preview" and add the menu item "Foo Bar" under it: