Folder Names "lua" Additional context I've written a more detailed description & motivation in my pull request ( #1542 ), but in summary: it's nice for tutorials repositories like exercism that ...

That code is from “ Programming in Lua by Roberto Ierusalimschy, which was written for Lua 5.0. Now Lua is at version 5.1, that work is a little out of date but still useful as a starting point.