Examine source code of Overleaf textarea

{
  "manifest_version": 2,
  "name": "Overleaf textarea",
  "version": "3.0.0",
  "description": "This plugin displays your text in a textarea so you can use spellcheck plugins like Grammarly.",
  "icons": {
    "16": "assets/icons/icon_16.png",
    "32": "assets/icons/icon_32.png",
    "48": "assets/icons/icon_48.png",
    "128": "assets/icons/icon_128.png"
  },
  "homepage_url": "https://github.com/abhijithvijayan/web-extension-starter",
  "permissions": [
    "https://overleaf.com/",
    "https://www.overleaf.com/",
    "*://*.overleaf.com/*",
    "storage",
    "contextMenus",
    "activeTab"
  ],
  "optional_permissions": [
    "http://*/*",
    "https://*/*"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "web_accessible_resources": [
    "js/page-script.bundle.js"
  ],
  "author": "Robin Dijkhof",
  "minimum_chrome_version": "49",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "assets/icons/icon_16.png",
      "32": "assets/icons/icon_32.png",
      "48": "assets/icons/icon_48.png",
      "128": "assets/icons/icon_128.png"
    }
  },
  "background": {
    "scripts": [
      "js/background.bundle.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.overleaf.com/*"
      ],
      "js": [
        "js/contentScript.bundle.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{2694ed88-83dd-c445-bd97-cb860fc66b7e}"
    }
  }
}