What is this?

Solution
From the description on that page:

This is a BGA socket which needs to be soldered to the motherboard using professional tools.

IOW: it's a replacement socket for Haswell-E and Broadwell-E based CPU systems (or for the more fanatical: DIY motherboard builder, if they exist.) It requires special soldering equipment to "weld" it to the system board as just a simple soldering iron or soldering gun won't be enough to properly do it without damaging the board and/or socket. It isn't for your average DIY person/hobbiest.
From the description on that page:

This is a BGA socket which needs to be soldered to the motherboard using professional tools.

IOW: it's a replacement socket for Haswell-E and Broadwell-E based CPU systems (or for the more fanatical: DIY motherboard builder, if they exist.) It requires special soldering equipment to "weld" it to the system board as just a simple soldering iron or soldering gun won't be enough to properly do it without damaging the board and/or socket. It isn't for your average DIY person/hobbiest.
 
Solution