This image is intended to aid with Connect plugin development. It's sole purpose is to write -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005, a JVM parameter to mcserver.vmoptions. The parameter enables remote Java debugging that you can use with IntelliJ, for example.
Original image: https://hub.docker.com/r/nextgenhealthcare/connect
Source repository: https://github.com/kpalang/mirth-plugin-dev-docker
Used in this guide: https://github.com/kpalang/mirth-plugin-guide/