Inspired by this question about the C64, I was curious if the Apple //e (and I suppose //c and IIgs, though not sure of ][+) somehow had a similar behavior. In short, we know that the Apple ROMs start at some location ($D000, I think) and are not modifiable. On the C64, you can flip a soft switch to bank out the ROMs and instead point to RAM mapped to the same location; this works because the C64 actually has 64KB of RAM despite the 8 or 16KB of ROM installed.
I was always under the impression that the //e shipped with 64KB on the motherboard. If you couldn't bank out the ROMs, this would mean that the upper 16KB effectively was wasted, no? Or is this functionality simply what the language card was doing to support Integer/AppleSoft BASIC switching?