Box 1: Markdown (.md)
Github understands several text formats, including .txt and .md. .md stands for a file written in Markdown.
Box 2: Mermaid diagrams -
Mermaid lets you create diagrams and visualizations using text and code.
It is a Javascript based diagramming and charting tool that renders Markdown-inspired text definitions to create and modify diagrams dynamically.
Reference:
https://ourcodingclub.github.io/tutorials/git/
https://mermaid-js.github.io/mermaid/#/