Examine source code of Usersnap

{
  "manifest_version": 2,
  "name": "__MSG_appName__",
  "short_name": "Usersnap",
  "description": "__MSG_appDescription__",
  "version": "3.0.2",
  "icons": {
    "16": "images/icon16.png",
    "128": "images/icon128.png"
  },
  "default_locale": "en",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "19": "images/icon19.png",
      "38": "images/icon38.png"
    },
    "default_title": "Usersnap",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "content_scripts": [
    {
      "matches": [
        "https://app.usersnap.com/browser-extension/"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "*://*.usersnap.com/*",
    "*://usersnap.com/*",
    "identity",
    "<all_urls>"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self';",
  "applications": {
    "gecko": {
      "id": "jid1-JVFdtm4BbUJ6wQ@jetpack"
    }
  }
}