Examine source code of Resizable Sidebar

{
  "manifest_version": 2,
  "name": "Resizable Sidebar",
  "version": "1.0",
  "description": "Adds a resizable sidebar to Firefox.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "storage"
  ],
  "sidebar_action": {
    "default_title": "Resizable Sidebar",
    "default_icon": "icon.png",
    "default_panel": "sidebar.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c3bfddea-f209-4beb-8903-d4fd03380613}"
    }
  }
}