Examine source code of Tabs Companion

{
  "manifest_version": 2,
  "version": "1.1.1",
  "name": "Tabs Companion",
  "description": "Adds a tab companion to manage tabs and clipboard.",
  "author": "fwkslabs",
  "developer": {
    "name": "fwkslabs"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tabscompanion@extensions.fwkslabs.com",
      "data_collection_permissions": {
        "required": [
          "websiteActivity"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "64": "icons/icon-64.png",
      "128": "icons/icon-128.png"
    },
    "default_title": "Tabs Companion",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "clipboardRead",
    "clipboardWrite",
    "notifications",
    "storage",
    "contextMenus"
  ]
}