/usr/bin/texdoc is in texlive-base 2017.20180305-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../share/texlive/texmf-dist/scripts/texdoc/texdoc.tlu
/usr/bin/../share/texlive/texmf-dist/scripts/texdoc/texdoc.tlu