Examine source code of Fly on the Screen

{
  "manifest_version": 3,
  "name": "Fly on the Screen",
  "version": "0.1.0",
  "description": "Add animated flies that walk around your web pages!",
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "action": {},
  "browser_specific_settings": {
    "gecko": {
      "id": "fly.on.the.screen@whitescreen.online",
      "strict_min_version": "58.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/content.js"
      ],
      "css": [
        "content/fly.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "popup-template.html",
        "icons/icon-128.png"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}