VideoCardz has a written summary over here.
We can immediately see differences in the PCB layout compared to the engineering sample, further confirming that this is a newer version of the DG2-512EU based model. Unlike the engineering sample, this card features a black PCB and silver shroud, a visible upgrade from green PCB and black shroud as seen on the previous unit. There has been no change to the power input though, it appears the flagship desktop model will only require 8-pin and 6-pin power connectors (estimated TDP at 225W). With the introduction of the PCI-Express 5.0 standard, power supply and graphics card manufacturers will be using a new Gen5 power connector. It is unclear whether Intel has plans to introduce this connector to Arc Alchemist GPUs though.The first ARC Alchemist cards are expected in early 2022. However, these will be mobile cards. The desktop variants are rumored to get a Q2 2022 launch.