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 MD?
A Markdown table is the one people actually write by hand: pipes between the cells, a row of dashes under the header. GitHub, docs sites and half the world's READMEs render them, and their one real subtlety is that a pipe inside a code span is text, not a column break.