/usr/share/xfig/Libraries/Optics/Lens/ is in xfig-libs 1:3.2.6a-2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/xfig/Libraries/Optics/Lens/asheric_1.fig
/usr/share/xfig/Libraries/Optics/Lens/asperic_2.fig
/usr/share/xfig/Libraries/Optics/Lens/biconvex_medium.fig
/usr/share/xfig/Libraries/Optics/Lens/biconvex_strong.fig
/usr/share/xfig/Libraries/Optics/Lens/biconvex_weak.fig
/usr/share/xfig/Libraries/Optics/Lens/convexconcave.fig
/usr/share/xfig/Libraries/Optics/Lens/planconcave_medium.fig
/usr/share/xfig/Libraries/Optics/Lens/planconcave_weak.fig
/usr/share/xfig/Libraries/Optics/Lens/planconvcave_strong.fig
/usr/share/xfig/Libraries/Optics/Lens/planconvex_medium.fig
/usr/share/xfig/Libraries/Optics/Lens/planconvex_strong.fig
/usr/share/xfig/Libraries/Optics/Lens/planconvex_weak.fig