Examine source code of Manga Navigator

{
  "manifest_version": 2,
  "name": "Manga Navigator",
  "version": "1.0",
  "description": "Navigate manga/manhwa pages with keyboard shortcuts (Left/Right arrow keys)",
  "permissions": [
    "activeTab",
    "storage",
    "<all_urls>",
    "contextMenus"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Manga Navigator Settings"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "manga-navigator@example.com"
    }
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  }
}