Email Tracking for Gmail and Mass Emailing

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 3,
  "name": "Email Tracking for Gmail and Mass Emailing",
  "description": "Experience the power of email tracking, Salesforce integration, and mass emails – right in your Gmail inbox.",
  "version": "2.0.20",
  "content_scripts": [
    {
      "matches": [
        "https://mail.google.com/*",
        "https://inbox.google.com/*"
      ],
      "css": [
        "./css/style.css",
        "./css/flatpickr.min.css"
      ],
      "js": [
        "./js/jquery-3.3.1.min.js",
        "content.js",
        "./js/flatpickr.js"
      ],
      "run_at": "document_end"
    }
  ],
  "background": {
    "service_worker": "background.js"
  },
  "permissions": [
    "storage",
    "notifications",
    "scripting"
  ],
  "host_permissions": [
    "https://mail.google.com/",
    "https://inbox.google.com/"
  ],
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "action": {
    "default_icon": "icon.png",
    "default_popup": "index.html"
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "css/*",
        "js/*",
        "images/*",
        "pages/*",
        "icon.png"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ]
    }
  ]
}