/usr/bin/mptopdf is in texlive-latex-base 2014.20141024-2+deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../share/texlive/texmf-dist/scripts/context/perl/mptopdf.pl
/usr/bin/../share/texlive/texmf-dist/scripts/context/perl/mptopdf.pl