Examine source code of GTA Mail

{
  "manifest_version": 3,
  "name": "GTA Mail",
  "version": "3.0",
  "description": "Adds GTA style visuals when sending email",
  "content_scripts": [
    {
      "js": [
        "scripts/content.js"
      ],
      "matches": [
        "https://mail.google.com/*",
        "https://outlook.live.com/*",
        "https://outlook.office.com/*"
      ]
    }
  ],
  "action": {
    "default_popup": "index.html",
    "default_icon": "images/gta_32.png"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "fonts/pricedown.ttf",
        "audio/gta_mission_passed_fixed.mp3"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "permissions": [
    "storage",
    "tabs"
  ],
  "icons": {
    "16": "images/gta_16.png",
    "32": "images/gta_32.png",
    "48": "images/gta_48.png",
    "64": "images/gta_64.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1a52cf9e-90f4-4490-9951-d10e272bb34b}",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}