What is Markdown?

Plain text with just enough punctuation to imply formatting, which is why it ended up as the default for READMEs, issues, wikis and notes. Its tables are the awkward part - a pipe-and-dash grid that's readable enough written by hand and tedious to maintain by hand.

What is SQL?

Not a file format so much as a language, but a file of INSERT statements is how data has always been moved into a database. Every engine will run one, and it's the least surprising thing to hand to a database that already exists.