Anti-bot CAPTCHA widget that helps digitize books by providing snippets of books for people to enter the text for. Owned by Google.
This site uses the viewport meta tag which means the content may be optimized for mobile content.
Previously Google Apps for Business. G Suite is a cloud-based productivity suite that helps you and your team connect and get work done from anywhere on any device. It's simple to setup, use and manage, allowing you to work smarter and focus on what really matters.
Varnish is an HTTP accelerator designed for content-heavy dynamic web sites. In contrast to other web accelerators, such as Squid, which began life as a client-side cache, or Apache and nginx, which are primarily origin servers, Varnish was designed as an HTTP accelerator. Varnish is focused exclusively on HTTP, unlike other pro...
nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
Open graph description entity tag
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook
Meta descriptions are HTML attributes that provide concise explanations of the contents of web pages. Meta descriptions are commonly used on search engine result pages (SERPs) to display preview snippets for a given page.
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical", or "preferred".
UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. It is the preferred encoding for web pages.