Wherever you see a box in the treemap that represents a folder, it
will have a little folder icon ( ),
a name (Program Files), and, if there is enough room, the
size of the folder, both as bytes (2.4 Gb) and as the number
of files and folders contained within it (29521). Of course,
it will also be sized relative to its contents, so boxes for
folders tend to be pretty big because folders tend to contain
more data than individual files.