Examine source code of Tabs2Clipboard

{
  "manifest_version": 2,
  "name": "Save tabs to clipboard",
  "version": "1.1.0",
  "browser_action": {
    "default_icon": {
      "19": "assets/blue-icon.svg",
      "38": "assets/blue-icon.svg"
    },
    "default_popup": "html/popup.html",
    "default_title": "Save all tabs to clipboard"
  },
  "icons": {
    "48": "assets/blue-icon.svg",
    "96": "assets/blue-icon.svg"
  },
  "permissions": [
    "tabs",
    "clipboardRead",
    "clipboardWrite"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a8d42794-c420-4cab-b32a-2952035e3ece}"
    }
  }
}