/usr/share/pixmaps/plt-48x48.png is in racket 5.1.3+dfsg1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/pixmaps/../racket/collects/icons/plt-48x48.png
/usr/share/pixmaps/../racket/collects/icons/plt-48x48.png