Description field in markbook

Hi Ross/Sandra,
Could you clarify what goes into the description fields as seen in these images?

Willpro, the main Description field (in the first image provides more detail about the column that can be included in the title (which is limited to a short number of characters). Hovering over the title in the Student/Parent markbook view brings up a popup with the description. I assumed the Weighting Description field works in a similar fashion, but will need @ross to confirm, as this is not a feature I use myself.