/usr/share/menu/itksnap is in itksnap 2.2.0-1.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8  | ?package(itksnap): \
    needs="X11" \
    section="Applications/Science/Medicine" \
    title="ITK-SNAP" \
    longtitle="3D Structure Segmentation" \
    icon="itksnap.xpm" \
    command="/usr/bin/itksnap" \
    hints="MRI"
 |