Google.com is built with the following tech stack:
Document Standards
Web App Manifest
Defines the attributes of a web app in a simple JSON file. It describes how the web app should appear on the users system and how it should launch.
Cascading Style Sheets
Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. Its most common application is to style web pages written in HTML
Javascript
JavaScript is a scripting language most often used for client-side web development.
Prefers Color Scheme
Defines how a page looks based on the color scheme choosen by the user for their desktop.
WAI-ARIA
A way to make Web content and Web applications more accessible to people with disabilities. It especially helps with dynamic content and advanced user interface controls developed with Ajax, HTML, JavaScript, and related technologies.
HTML5 DocType
The DOCTYPE is a required preamble for HTML5 websites.
HTML 5 Specific Tags
This page contains tags that are specific to an HTML 5 implementation.
X-XSS-Protection
X-XSS-Protection is a HTTP header set by Internet Explorer 8+. This header lets domains toggle on and off the "XSS Filter" of IE8, which prevents some categories of XSS attacks.
Content Type Options
Used to disable MIME-sniffing for a particular HTTP response.
Strict Transport Security
The HTTP Strict-Transport-Security (HSTS) header instructs the browser to only use https.
Document Encoding
UTF-8
UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. It is the preferred encoding for web pages.
Mobile
Viewport Meta
This page uses the viewport meta tag which means the content may be optimized for mobile content.
Apple Mobile Web Clips Icon
This page contains an icon for iPhone, iPad and iTouch devices.
SSL Certificates
HSTS
Forces browsers to only communicate with the site using HTTPS.