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 game dev, I have to say this kind of criticism is too vague to be of any use