* `dug_too_fast`
* `minetest.register_on_chat_message(func(name, message))`
* Called always when a player says something
+ * Return `true` to mark the message as handled, which means that it will not be sent to other players
* `minetest.register_on_player_receive_fields(func(player, formname, fields))`
* Called when a button is pressed in player's inventory form
* Newest functions are called first