from: https: //en.wikipedia.org/wiki/Q_source
we get this information (a copy/paste):
"The Q source (also Q document, Q Gospel, or Q from German: Quelle, meaning "source") is a hypothetical written collection of primarily Jesus' sayings (logia). Q is part of the common material found in the Gospels of Matthew and Luke but not in the Gospel of Mark. According to this hypothesis, this material was drawn from the early Church's Oral Tradition."
we've been down this slide before here.