/usr/share/lua/5.2/json/util.lua is in lua-json 1.3.3-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/lua/5.2/json/../../5.1/json/util.lua
/usr/share/lua/5.2/json/../../5.1/json/util.lua