/usr/share/lua/5.2/lyaml/functional.lua is in lua-yaml 6.1-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/lua/5.2/lyaml/../../5.1/lyaml/functional.lua
/usr/share/lua/5.2/lyaml/../../5.1/lyaml/functional.lua