Examine source code of Pass Me

{
  "manifest_version": 2,
  "name": "Passme",
  "version": "1.0.1",
  "icons": {
    "16": "icons/main/password_w_16.png",
    "48": "icons/main/password_w_48.png",
    "96": "icons/main/password_w_96.png",
    "128": "icons/main/password_w_128.png"
  },
  "description": "Add a button on every password input to allow explore the password written.",
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "*://*/*"
      ],
      "js": [
        "script.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "icons/*"
  ]
}