We decided to avoid using “free” or “libre” in the name because we don’t think it does the project justice.

This is the best project naming decision you could make in the FOSS space.

“Luanti” is a wordplay on the Finnish word luonti (“creation”) and the programming language Minetest Luanti employs for games and mods, Lua. 

And this is among the worst. I mean the programming language part. Even Rust projects strive to avoid this sort of naming, so focus on your project's purpose and identity, cuz nobody that doesn't actively do development cares, especially users. Roblox is a platform that involves playing and creating games, also uses Lua as its language of choice but you know what's actively missing from it's title? The name of the Lua language!

TLDR: They avoided putting the FOSS-ness in the name but put the programming language. To-may-to, to-mah-to. They avoid one naming fallacy only to embrace another.