MCL is the software running on the Megacommand which is an open source Midi-controller specialised for the Machinedrum. It is quite a nifty tool, allowing to use features of newer elektrons on the old silver boxes. The Dev’s that published the unofficial firmware are also the ones that develop the megacommand. If you are into individual track lenght’s, tracker-style pattern management, extended midi sequencing, some new mixing options and much more you should look into the elektronauts thread regarding the MCL:
There also should be a link to the dedicated discord regarding MD.X and the MC