Examine source code of Copy Article URLs

{
  "manifest_version": 2,
  "name": "Copy Article URLs",
  "version": "1.0",
  "description": "A Firefox add-on that copies all the URLs in the current article.",
  "icons": {
    "48": "yellow.png"
  },
  "browser_action": {
    "default_title": "Copy Article URLs"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "javascript.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{85fd2024-b5ff-4c4a-a517-e01ccd76758a}"
    }
  }
}