"Specify names and types for user-defined columns or create additional columns. The FCP Preset button automatically sets user column names to match Final Cut Pro. Use the Built-in Fields button to customise the names of pre-defined attributes. You can also define Marker Categories from this tab. (Professional Edition only)"
Be careful with this tab however, as you can really muck things up in your db without realizing it. (Especially if you swap files with another CatDV user.)