They are hoping to replace the proprietary baseboard management controller firmware with an open-source solution using OpenBMC. They are hoping to do this not only for the sake of having a fully-free server/workstation motherboard but also for addressing security holes in the proprietary firmware and add missing features while also allowing Coreboot to interact with this BMC.
Raptor Engineering estimates it will cost around $50,000 USD to bring Facebook's OpenBMC stack to this particular ASUS KGPE-D16 motherboard, of which they themselves are sponsoring $30k of the cost and have already around $10k sponsored by the community and they continue crowdfunding for the rest.
For those wishing to learn more about their latest focus on tackling the BMC of this ASUS motherboard can visit this Raptor Engineering page. Those wanting to learn about Facebook's OpenBMC project can visit their GitHub site.
The KGPE-D16 motherboard is still available for retail channels for around $400~420 new or under $300 used. This SSI EEB server motherboard that supports Coreboot currently but without the BMC support is capable of supporting two Opteron 6300/6200/6100 series CPUs, up to sixteen DDR3 DIMMs, PCI Express, etc. Those curious about this board can still find it listed at Amazon.com.