Examine source code of Time Zone Changer

{
  "manifest_version": 3,
  "version": "1.0.0",
  "name": "Time Zone Changer",
  "description": "Easy time zone change.",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "64": "icons/64.png",
    "128": "icons/128.png"
  },
  "action": {
    "default_title": "Time Zone Changer",
    "default_icon": {
      "16": "icons/16.png",
      "32": "icons/32.png",
      "48": "icons/48.png",
      "64": "icons/64.png"
    }
  },
  "permissions": [
    "storage",
    "scripting",
    "contextMenus",
    "webNavigation"
  ],
  "host_permissions": [
    "*://*/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6a9758a9-9682-44ff-889e-0da96e63d938}"
    }
  }
}