/usr/share/applications/libreoffice-math.desktop is in libreoffice-math 1:4.3.3-2+deb8u11.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libreoffice/share/xdg/math.desktop
/usr/lib/libreoffice/share/xdg/math.desktop