Examine source code of On this day Sidebar

{
  "manifest_version": 2,
  "name": "On this day Sidebar",
  "version": "0.1",
  "description": "Displays a sidebar with the On this day page from Wikipedia.",
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "73.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{ea9e3e91-a9d4-4f26-b478-aafc046e517d}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "192": "icons/icon32.png"
  },
  "sidebar_action": {
    "default_icon": {
      "192": "icons/icon32.png"
    },
    "default_title": "On this day",
    "default_panel": "index.html"
  },
  "browser_action": {
    "default_icon": {
      "192": "icons/icon32.png"
    },
    "theme_icons": [
      {
        "light": "/icons/icon32.png",
        "dark": "/icons/icon32.png",
        "size": 192
      }
    ]
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "commands": {
    "_execute_sidebar_action": {
      "suggested_key": {
        "default": "Ctrl+Alt+F"
      }
    }
  }
}