Examine source code of Rastchin

{
  "background": {
    "scripts": [
      "./src/background.js"
    ],
    "persistent": false
  },
  "commands": {
    "LTR": {
      "description": "Enable left to right",
      "suggested_key": {
        "default": "Ctrl+Shift+E"
      }
    },
    "RTL": {
      "description": "Enable right to left",
      "suggested_key": {
        "default": "Ctrl+Shift+H"
      }
    }
  },
  "description": "This extension allows you to change language direction.",
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAp5/Oe9EhQThJcaSzd3L8RJjNEzRgwoH/iAwpJHOA9CRzFfeKrmc+VMRu9VaXgQk+Hj+BRsRAAXm3gHfq8PeWXOD4MglPUgroyDiiz1ep6DEsDDI9zEQAcWAatD/wDco92ojkerdKqs8VEZ3nAbW7gvjf3ZwqVilJMKqwNvxuDgDec3go/Sl8FhkuXylLvy+i4+hkbwyUPiyJJMt+fE0v0DC2wPG6BCtsOFWe/ApSBaytWf8QoeNZfMMLBo7KWzqeEZmhiC/Tdt5CAPOAvVlRnd8GzEqOCTuA5DgqkrEFBlcIHigzMSuQ3c8F4LNhkvQ14XVBMGdhyVlZl2A+KRg8WwIDAQAB",
  "manifest_version": 2,
  "name": "LTR-RTL",
  "permissions": [
    "contextMenus",
    "tabs",
    "<all_urls>",
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "./src/content.js"
      ]
    }
  ],
  "update_url": "https://clients2.google.com/service/update2/crx",
  "version": "1.1",
  "icons": {
    "16": "./assets/icon16.png",
    "24": "./assets/icon24.png",
    "32": "./assets/icon32.png",
    "64": "./assets/icon64.png",
    "128": "./assets/icon128.png",
    "256": "./assets/icon256.png",
    "512": "./assets/icon512.png"
  }
}