/etc/fonts/conf.d/89-tlwg-umpush-synthetic.conf is in fonts-tlwg-umpush 1:0.6.4-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/fontconfig/conf.avail/89-tlwg-umpush-synthetic.conf
/usr/share/fontconfig/conf.avail/89-tlwg-umpush-synthetic.conf