rP7653 introduced the "debug-print" simulation command which consumes a string provided by the GUI, sends it to the simulation and then shows that string in the terminal output.
But the JS console already has that function, a complete eval since rP469, so it can be deleted without any impact on debuggability. Aside from that this should really not be a simulation command (let alone a command available to every client).
rP14991 enabled translations for the tutorial AI sent messages (though GUIInterface) by inserting a new type "aichat".
However it (1) added the "aichat" case not only for message parsing by the simulation GUIInterface notifications but also for the NetClient message parsing, but the NetClient never sends this message, so that case is dead and misleading (certainly I was fooled into assuming it had a reason to exist ever since)
and (2) the untranslated "chat" simulation command has no more use case, since user provided chat strings should not be sent through the simulation because chat should also be sent during extended match (simulation) pauses, and since the code-provided strings should always be translated (even if they shouldn't it would be nicer to add a property translated = false)
rP17796 added translateMessage to an aichat GUIInterface notification that isn't used by that type (only by 'timenotifications', i.e. !type || type == "message").