main-menu
Domain: JupyterLab GUI
🎯 Motivation
The top menu bar in JupyterLab (File, Edit, View, Run, etc.). Extensions add items via app.commands and MainMenu.
📋 Concrete Example
Use mainMenu.fileMenu.addGroup([{command: 'mycmd'}]) to insert your command into the File menu.
🔗 Analogy
The main menu is a restaurant menu — each section lists dishes (commands) you can order by clicking.