Certain scenarios (e.g. not running any Applesoft program at all since booting DOS 3.3) can make DOS 3.3 consider cc65 device input (e.g. getchar()) that reads a CR interpreting the command in the keyboard buffer. Setting the hibyte of the Applesoft currently executed line number to some value <> $FF (beside setting the input prompt to some value <> ']') makes DOS 3.3 understand that we're not in intermediate mode and that therefore I/O not preceded with ctrl-d mustn't be fiddled with (see DOS 3.3 routine at $A65E).
The way we want to use the INITBSS segment - and especially the fact that it won't have the type bss on all ROM based targets - means that the name INITBSS is misleading. After all INIT is the best name from my perspective as it serves several purposes and therefore needs a rather generic name.
Unfortunately this means that the current INIT segment needs to be renamed too. Looking for a short (ideally 4 letter) name I came up with ONCE as it contains all code (and data) accessed only once during initialization.