I am having trouble remembering how to make a layer have a description. The column is there in 'Layer Settings' but I can give a particular later a name. That is possible isn't it? I thought I had done that in the past.
Nemo
The description is technically for the layer category, not the layer itself. However, if the category only contains one layer, the end result is essentially the same.
To create a category:
Turn on the "category display", right click in some white space and choose "new category", give the category a name, right click in the description column to edit the category description. Now you can add one or more layers to the new category by turning off the "category display" and selecting one or more layers, right clicking on one and choosing add to category -> category name.