Examine source code of ViewPass

{
  "manifest_version": 2,
  "name": "ViewPass",
  "version": "1.0.1",
  "description": "Show password field text",
  "icons": {
    "32": "icons/32.png",
    "48": "icons/48.png",
    "64": "icons/64.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "script/showpassword.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{03f127ed-49a6-4cac-b5f7-bf657311d54a}"
    }
  }
}