The dynamic keyword in Art.Domain project

I was navigating through the Spark framework and I was digging into the Core.cs file to understand the repository pattern that is getting used when I stumbled on this head scratcher.  In the InitMap method I see that within your foreach loop of the columns I am a getting intellisense on the dynamic keyword of column (see attached screenshot).  I'm wondering how this was achieved?  I can't find any way of replicating the same sort of intellisense on a dynamic keyword.

Best regards,
Jeff