A Readme file is a file that describes the purpose of the repository and gives hints about what the code does, how to compile / use it, etc.
The .md extension means Markdown , which is a type of file that can be read in plain text, but can also be easily converted to HTML to display special elements.
Stack overflow occurs for markup syntax for questions and answers, so here are a few examples of what Markdown can do:
Headings
References
The Markdown code I used for to create them:
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