No rocket science here :-)
This part allows you to mount a 2020 profile to a 3030 profile in a specific way. In my case I needed to secure two 2020 profiles with linear rails to my old Rebel2 printer so that I can put the MK52 heated bed on that machine.
PS: the mounts work just fine, however I haven't fully implemented this change yet, hoping to do so before New Years Eve :-)
The author marked this model as their own original creation.