Examine source code of Report

{
  "manifest_version": 2,
  "name": "Report",
  "version": "1.0",
  "description": "Adds a browser action icon to the toolbar. Click the button to choose a beast. The active tab's body content is then replaced with a picture of the chosen beast. See https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Examples#beastify",
  "icons": {
    "48": "logo/48-48.png"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "devtools"
  ],
  "sidebar_action": {
    "default_icon": {
      "16": "logo/16-16.png",
      "32": "logo/32-32.png"
    },
    "default_title": "Report",
    "default_panel": "popup/choose_beast.html",
    "open_at_install": true
  },
  "browser_action": {
    "default_icon": "logo/32-32.png",
    "default_title": "Report",
    "default_popup": "popup/choose_beast.html"
  }
}