Examine source code of Didtheyreadit.com Web Plugin

{
  "applications": {
    "gecko": {
      "id": "wegmo@didtheyreadit.com"
    }
  },
  "background": {
    "page": "background.html"
  },
  "content_scripts": [
    {
      "js": [
        "jquery.js",
        "yahoo.js"
      ],
      "matches": [
        "*://mail.yahoo.com/*",
        "*://mg.mail.yahoo.com/*"
      ]
    },
    {
      "js": [
        "jquery.js",
        "microsoft.js"
      ],
      "matches": [
        "*://outlook.live.com/*"
      ]
    },
    {
      "js": [
        "jquery.js",
        "gmail.js"
      ],
      "matches": [
        "*://mail.google.com/mail/u/0/h/*"
      ]
    },
    {
      "js": [
        "jquery.js",
        "inbox.js"
      ],
      "matches": [
        "*://inbox.google.com/*"
      ]
    },
    {
      "js": [
        "jquery.js",
        "gmail_web2.js"
      ],
      "matches": [
        "*://mail.google.com/mail/*"
      ]
    }
  ],
  "content_security_policy": "default-src 'self'; connect-src http: https:; script-src 'self'; img-src 'self' data:; style-src 'self' 'unsafe-inline'; frame-src 'self' about: ",
  "description": "Offers email tracking for popular webmail systems",
  "icons": {
    "16": "green16.png",
    "48": "green48.png",
    "128": "green128.png"
  },
  "manifest_version": 2,
  "name": "Didtheyreadit.com Web Plugin",
  "permissions": [
    "*://*.google.com/*",
    "*://mail.yahoo.com/*",
    "*://mg.mail.yahoo.com/*",
    "*://outlook.live.com/*",
    "*://inbox.google.com/*",
    "http://127.0.0.1/",
    "https://local.vradd.com/"
  ],
  "version": "2.91",
  "web_accessible_resources": [
    "jquery.js",
    "yahooHook.js",
    "microsoftHook.js",
    "inboxHook.js",
    "images/on.ico",
    "images/off.ico"
  ]
}