.GO File Extension
What is a GO file?
Source code for a program written in Go, a programming language originally developed by Google; contains code written in plain text format that must be compiled before being run as a program.
Go is loosely based off of the programming language C, which uses the .C file extension for its source code.
NOTE: GO files can be edited using a simple text editor but there are also many IDEs that support GO with the use of plugins.