Examine source code of Simple URL Extractor

{
  "manifest_version": 2,
  "name": "Simple URL Extractor",
  "version": "3.0.0",
  "description": "Extract URLs from selected text via context menu and open them quickly.",
  "icons": {
    "16": "128.png",
    "48": "128.png",
    "128": "128.png"
  },
  "permissions": [
    "contextMenus",
    "storage",
    "activeTab",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "128.png",
      "48": "128.png",
      "128": "128.png"
    }
  },
  "commands": {
    "extract-urls-shortcut": {
      "suggested_key": {
        "default": "Alt+Shift+X",
        "mac": "Alt+Shift+X"
      },
      "description": "Extract URLs from current selection"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "simple-url-extractor@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}