that means that i haven't installed it at the moment - so i can't look it up. sorry.

EDIT: but the important scan should be the root-scan. there the folders are sorted by their size.

/home doesn't really matter because this is your biggest partition with about 27GB.

/sys (~18MB) and
/lib (~15MB) is where your firmware/system files are stored.

/var (~38MB) is where your catalogue packages are stored. if this one uses much memory you may want to disable some catalogues. (i have the 4 default catalogues + testing + devel activated. that's why it's ~38MB big.)

/usr (~268MB) should have your attention:
with ../lib (~185MB) where the localizations are stored and some needed libraries.
and ../share (~57MB) where mostly themes, icons, fonts, sounds, etc are stored and some localizations.

if anyone if these or the other folders listed in the tree-view of storageusage are using too much memory (you can orientate yourself on my (~ $size MB) values) it may be something wrong. (not optified packages for example)