I'm migrating 2007 to 2010. I've found lists and libraries that have a column of type ClientId. It's actually one of the options in the Create Column dialog. Of course, it doesn't exist on my 2010 farm. I've found a Site Collection Feature named Client Column for which I have a warm feeling that it is the culprit. How do I go about figuring out what this is; opening it up and reverse engineering such a thing.
Also, if you have a warmer feeling, how would you get to the bottom of that data type?
PS- Its functionality is that it presents a control that is a "single line of text" but when you start typing into it it autocompletes the entry from a list of account numbers from what I assume is an external data source being the Dynamics CRM database.