Hi,
You can open your Extension, find the LingoCloud Extension, in the bottom of the page, you can see the "Delete" or "Uninstall", click it.
您好，您可以打开火狐浏览器的“管理您的扩展和主题”，找到“彩云小译”，打开网页后拉到最底部，您可以看到“删除" 该按钮为卸载按钮。
谢谢