Currently, we have Pants as the primary build tool, but we still have pom.xml files and we still auto-generate BUILD files from them. This quarter, Garrett and I are focusing on getting us out of the auto-genration business. That's why I'm working on this parallel testing feature (we still have a small CI that runs maven to run some tests.) We've been planning since last year for primary responsibilities to be moved to a team in San Francisco once we successfully remove all remnants of maven from the build. @brash-oxygen-26029 (Chris Heisterkamp) is on that team.