Software now appears to be available on flightsim.to
Multiplayer Model Matching (M3) for Microsoft Flight Simulator | MSFS
First impressions look really good, hoping to have a lot fun with this. Finally solving all the unknown aircraft doing inappropriate manoeuvres.
More recent announcement post here
[RELEASE] Multiplayer Model Matching (M3) | M3 Team - General Discussion & Community Support / 3rd Party Product Announcements - Microsoft Flight Simulator Forums
@flyndive thanks for this, keep up the good work.