This is the dev documentation for an unreleased version of MPF!
This is the documentation for MPF 0.56, which is the “dev” (next) release of MPF that is a work-in-progress. Unless you’re specifically looking for this version, you probably want to use the version of documentation called “latest” which is for the latest released version of MPF. That documentation is at docs.missionpinball.org/en/latest.
The multiball lock device (name) has just locked one additional ball.