Examine source code of Furigana Toggle

{
  "manifest_version": 3,
  "name": "Furigana Toggle",
  "version": "2.0.0",
  "description": "Toggle furigana on and off.",
  "author": "Darren Lester",
  "permissions": [
    "storage",
    "tabs",
    "activeTab",
    "scripting"
  ],
  "host_permissions": [
    "*://*/*"
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "furigana-toggle.css"
      ],
      "matches": [
        "*://*/*"
      ]
    }
  ],
  "background": {
    "scripts": [
      "service_worker.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "action": {
    "default_icon": {
      "16": "./logo_16.png",
      "48": "./logo_48.png",
      "128": "./logo_128.png"
    },
    "default_title": "Furigana Toggle"
  },
  "options_ui": {
    "page": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "furiganatoggle@darrenlester.com",
      "strict_min_version": "53.0"
    }
  }
}