Shimano has officially unveiled ... GRX 2x12-speed parts including the crankset and a Di2 battery, this puts the price of a complete groupset at around $2,533/£2,100. That’s close to $1,000 ...
In this case, Shimano went off book with their DI2 groupset, leaving [kwakeham] with a reverse engineering job on his hands. [kwakeham] gives us a great example of how to approach reverse engineering.