Examine source code of Copy Page URL

{
  "manifest_version": 2,
  "name": "Copy Page URL",
  "description": "Adds browser action icon to toolbar to copy web page URL.",
  "author": "Stanislav Burdukowsky",
  "homepage_url": "https://github.com/burdukowsky/copy-page-url-firefox-extension",
  "version": "1.3resigned1",
  "icons": {
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "permissions": [
    "activeTab",
    "clipboardWrite"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "icons/16.png",
      "32": "icons/32.png"
    },
    "default_title": "Copy Page URL"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{012dd417-aaaa-4f9b-86a3-bec0fbadb0b3}"
    }
  }
}