Examine source code of Reveal Password

{
  "manifest_version": 2,
  "name": "ShowPass",
  "version": "1.1",
  "description": "A simple utility to see autofilled saved passwords with double click on any page. Double click the password and it should show it in plain text.",
  "icons": {
    "48": "icon.png",
    "96": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "script.js"
      ]
    }
  ]
}