Examine source code of Workspace Switcher

{
  "manifest_version": 2,
  "name": "Workspace Switcher",
  "description": "Group your tabs into customizable workspaces and instantly switch between them.",
  "version": "1.0.3",
  "permissions": [
    "tabs",
    "activeTab",
    "tabHide",
    "storage"
  ],
  "browser_action": {
    "default_title": "Workspace Switcher",
    "default_popup": "popup/context-switch.html"
  },
  "background": {
    "scripts": [
      "utils.js",
      "background.js"
    ],
    "persistent": true
  },
  "options_ui": {
    "page": "settings/settings.html",
    "open_in_tab": true
  },
  "icons": {
    "32": "icons/context-switch-icon-32.png",
    "48": "icons/context-switch-icon-48.png",
    "92": "icons/context-switch-icon-92.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4ef53ad6-772d-4a81-b931-d8abe91baabc}"
    }
  }
}