Examine source code of TextRecruit Everywhere Extension

{
  "manifest_version": 2,
  "name": "TextRecruit Extension",
  "short_name": "TextRecruit Extension",
  "homepage_url": "https://www.icims.com/products/talent-cloud-platform/text-engagement/",
  "description": "The TextRecruit Everywhere Extension helps recruiters text candidates from their ATS, job boards, or LinkedIn.",
  "version": "3.3.1",
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "permissions": [
    "storage",
    "https://*/*",
    "http://*/*"
  ],
  "browser_action": {
    "default_icon": "./img/tr_bubble_grey_48.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "incognito": "not_allowed",
  "web_accessible_resources": [
    "img/*",
    "iframe.html",
    "iframe.js",
    "disabled.html"
  ],
  "content_scripts": [
    {
      "run_at": "document_idle",
      "matches": [
        "<all_urls>"
      ],
      "exclude_matches": [
        "https://hangouts.google.com/*",
        "*://mail.google.com/*",
        "https://sso.texasroadhouse.com/*",
        "https://js.stripe.com/*",
        "https://login.microsoftonline.com/*",
        "https://secure.ace.advertising.com/*",
        "http://127.0.0.1/*",
        "https://*.icimsmco.net/*",
        "https://*.slack.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "all_frames": true
    },
    {
      "run_at": "document_idle",
      "matches": [
        "https://mail.google.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "all_frames": false
    }
  ],
  "icons": {
    "48": "./img/icon48.png",
    "128": "./img/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{dd0515e7-1a13-4cb7-a93c-ca5a012bb155}"
    }
  }
}