This RFC documents the format used for Comma-Separated Values (CSV) files and registers the associated MIME type "text/csv". This memo provides information for the Internet community.
I noticed a repository’s .gitattributes entry for *.csv used text eol=crlf so I investigated and found this.
Don’t worry, it’s not really standardised despite this attempt. You can use UNIX line endings and nothing bad will happen.
Unless you open it in Excel. In which case bad things will happen no matter what you have in the CSV…