Word about a P2P feature for Windows Update in Windows 10 began circulating towards the end of 2014 thanks to a dummy UI found in one of the early Windows 10 builds which showcased P2P abilities. In build 10036 which leaked recently, it appears that feature is still being built and improved upon.
For those who don't know, P2P allows users to download Windows Updates from one PC, and then distribute it to other PCs on your network. This will save bandwidth for those who are on metered connections. It's not entirely clear if said feature works correctly just yet, as no updates for build 10036 have been issued.
The recent leak of build 10036 has unveiled a number of new additions which the company has been working on. The UI is being improved, and additional features are being added throughout the operating system. Keep checking WinBeta for more regarding Windows 10 and the latest leak.