Age HTTP Header - Original Server Response

   The Age header contains the time in seconds the object has been in a proxy cache.

SPF

   The Sender Policy Framework (SPF) is an email-authentication technique which is used to prevent spammers from sending messages on behalf of your domain. With SPF an organisation can publish authorized mail servers.

G Suite

   formerly Google Apps for Work and Google Apps for Your Domain is a brand of cloud computing, productivity and collaboration tools, software and products developed by Google.

Server partial requests support

   The Accept-Ranges response HTTP header is a marker used by the server to advertise its support of partial requests. The value of this field indicates the unit that can be used to define a range.

Apache 2

   The Apache HTTP Server, colloquially called Apache, is free and open-source cross-platform web server software, released under the terms of Apache License 2.0. Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.