What is NDJSON?
NDJSON is one JSON object per line, and nothing wrapping them. That single change makes it streamable - a program can handle a line at a time instead of holding the whole array in memory - which is why logs, data exports and machine-learning datasets ship in it.
What is SQL?
A table as SQL is a CREATE TABLE and a run of INSERT statements: the form data takes when it is going into a database rather than a spreadsheet. Dialects differ on quoting, so this is written to the ANSI standard and says so in the file's first line.