So I did a bit of reading, and discovered that there is a utility deborphan
that shows, err, orphaned libs. So I installed it using apt-get install deborphan
As apt-get was doing its stuff, it displayed:
"The following packages were automatically installed and are no longer required:
libchipcard-libgwenhywfar47-plugins libswfdec-0.6-90 libfreebob0 [...]
...Use 'apt-get autoremove' to remove them.
So, I did apt-get autoremove
, and lo and behold, around 170 MB of stuff was cleaned up from /usr/lib.
So that seems to have sorted that.