THIS MIGHT SURPRISE YOU
The answer
Disagree. Q, if it existed, is known only from what both Matthew and Luke chose to keep. It may have held material neither used, even a story of Jesus's death, and no one would ever know.
Why it’s interesting
What both have, like the Lord's Prayer, is counted as Q (Matthew 6:9-13; Luke 11:2-4). But a saying only Matthew has could be Q material that Luke left out, so the edges of Q blur.
Open question
Learn the Bible.
Not just the stories, but the history, authorship, and scholarship behind it.