/usr/share/lua/5.2/wsapi/fastcgi.lua is in lua-wsapi 1.6.1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/lua/5.2/wsapi/../../5.1/wsapi/fastcgi.lua
/usr/share/lua/5.2/wsapi/../../5.1/wsapi/fastcgi.lua