The TXT file type is primarily associated with 'Text File'. Open in Notepad, WordPad, or many other programs designated as text editors. A true text file will be pure ASCII text with no formatting.

PNG (Portable Network Graphics) is an image file format designed to store raster graphics. It is associated with ".png" file extension. Use this tag for questions involving this specific format.

A shader is a program to perform calculations on geometry or pixel data in computer graphics.

The UITabBarController class implements a specialized view controller that manages a radio-style selection interface. This tab bar interface displays tabs at the bottom of the window for selecting between the different modes and for displaying the views for that mode. This class is generally used as-is but may be subclassed in iOS 6 and later.

RSA is a common public key algorithm, which can be used for encryption and signature. It is a core component of most the security protocols used on the Internet, including the SSL/TLS protocol suite. For questions about IBM Rational Software Architect, use the rational-rsa tag.

Chef Infra (formerly just Chef) is a DevOps tool for scripting server configurations in Ruby (called cookbooks). Questions should pertain to the Ruby portions of coding. General DevOps questions may be asked on https://devops.stackexchange.com

Apache Flink is an open source platform for scalable batch and stream data processing. Flink supports batch and streaming analytics, in one system. Analytical programs can be written in concise and elegant APIs in Java and Scala.

The Abstract Window Toolkit (AWT) is Java's original platform-independent windowing, graphics, and user-interface widget toolkit.

A variable is undefined if it has not been assigned a value.

Use this tag for questions related to JavaScript objects.

A tree data structure in which each node has at most two child nodes.