Examine source code of Minimal To Do List

{
  "manifest_version": 2,
  "name": "Minimal To Do List",
  "description": "create a minimal to do list",
  "version": "1.0",
  "action": {
    "default_icon": "img/todo_icon.png",
    "default_title": "stay productive",
    "default_popup": "todo.html"
  },
  "icons": {
    "16": "img/todo_icon.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{eb648a02-27f1-440c-b435-f22cb3c8b8f8}"
    }
  }
}