Meta Description

   A meta description is a 160-character snippet, a meta tag in HTML, that summarizes a page`s content. this website is having meta description of the following : American Memory is a gateway to rich primary source materials relating to the history and culture of the United States. The site offers more than 7 million digital items from more than 100 historical collections.

Meta keywords

   Meta keywords are types of meta tags in the HTML source code of a webpage. They describe the content of a website shortly and concisely,this website is using the following keywords: library congress american memory historical collections national digital library prints photographs manuscripts books motion pictures music sound recordings performing arts

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.

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.

Nginx 1.10.1

   Nginx is a web server which can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache. The software was created by Igor Sysoev and first publicly released in 2004. A company of the same name was founded in 2011 to provide support and Nginx plus paid software.

Chunked transfer encoding

   Chunked transfer encoding is a streaming data transfer mechanism available in version 1.1 of the Hypertext Transfer Protocol (HTTP). In chunked transfer encoding, the data stream is divided into a series of non-overlapping "chunks"