Examine source code of Stack Copy Button

{
  "manifest_version": 2,
  "name": "Stack Copy Button",
  "author": "MrMino",
  "description": "A copy button for Stack Overflow code boxes",
  "version": "1.1.3resigned1",
  "browser_action": {
    "default_icon": "icon32.png"
  },
  "icons": {
    "32": "icon32.png",
    "128": "icon128.png"
  },
  "permissions": [
    "*://stackoverflow.com/*",
    "clipboardWrite"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.stackoverflow.com/*"
      ],
      "js": [
        "jquery-1.12.3.min.js",
        "copybox.min.js"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "stack.copy.button@mr.mino"
    }
  }
}