That's all server-side code, which is the normal thing for luanti mods and games.

Client-side modding is currently a bit crude and limited, and requires a bit of funky manual installation, but allows you to read and alter some things on the client that aren't available to the server code. Client-side modding (CSM) was added a bit prematurely and is still in kind of a proof-of-concept stage; it was intended to be a step towards server-sent client-side modding (SSCSM) which will allow games to customize the behavior of the client.

For Exile we have an optional CSM for handling special keypresses, since reading key sequences can be difficult with lag over multiplayer, but 99.9% of our code is just the regular server-side code.

As a developer of a game for this engine that's very much intended to NOT be a Minecraft clone, it's frustrating to see comments about the engine saying that "A Minecraft clone is exactly what it is." It does make me feel better about the name change, though. Maybe there'll be less of that backwards-looking sort of thing in the future.

The sleeping spot is terrible, it's basically just marking out a spot and laying on the cold, hard ground. Useful when you've fallen in a hole and can't get out, but if you've got access to grassy plants, make a sleeping mat from eight of them, it's much better.

Also to regain energy you'll need to be comfortable, if the surrounding temperature is too cold or hot it can prevent resting. Get a fire and a roof of some kind -- a shallow cave or tree works, though trees lose their leaves in winter which makes them less useful.

We have a tutorial in the works to help newbies with these things, but it's not ready yet.