Your friend is sending you a file with Firefox Send, a service that allows you to share files with a safe, private, and encrypted link that automatically expires to ensure your stuff does not remain online forever.
您的朋友使用 Firefox Send 向您发送一个文件。该服务允许用户以安全、私密、受加密的链接分享一个文件，链接到期后文件将从网上彻底抹除。