I chose Markdown as the first project language file for this project (seanpm2001/Candroid-Catalogue) as this project is just a documentation set (a catalog article, and some tables) that is written in Markdown. Markdown is the most fitting language for a project language file here. It is getting its own project language file, starting here.
This is an instance in which I am using Markdown as a project language file, as I learned how to make the GitHub linguist recognize Markdown as a language. I found this out when snooping around on Apple/Swift Evolution if you want to do this yourself, simply add this to your .gitattributes file (if you haven't created one yet, make it now, do not add anything else to the file name but .gitattributes)
*.md linguist-detectable=true
*.md linguist-documentation=false
*.md linguist-language=MarkdownAdvanced version:
# Markdown (*.md, *.mkd, *.mdown, *.markdown)
*.md linguist-detectable=true
*.md linguist-documentation=false
*.md linguist-language=Markdown
*.mkd linguist-detectable=true
*.mkd linguist-documentation=false
*.mkd linguist-language=Markdown
*.mdown linguist-detectable=true
*.mdown linguist-documentation=false
*.mdown linguist-language=Markdown
*.markdown linguist-detectable=true
*.markdown linguist-documentation=false
*.markdown linguist-language=MarkdownFile type: Markdown document (*.md, *.mkd, *.mdown, *.markdown)
File version: 1 (2022, Thursday, December 1st at 4:07 pm PST)
Line count (including blank lines and compiler line): 45