Examine source code of ep-rtl-extension

{
  "manifest_version": 2,
  "name": "RTL/LTR Layout Toggle",
  "version": "3.7",
  "description": "Toggles the entire page layout between LTR and RTL from the context menu.",
  "author": "mohammad rahimi",
  "permissions": [
    "contextMenus",
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "16": "icons/icon-48.png",
    "32": "icons/icon-48.png",
    "48": "icons/icon-48.png",
    "96": "icons/icon-48.png",
    "128": "icons/icon-48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{43e8428e-6752-42c8-bada-9a37f50e6660}"
    }
  }
}