> Perhaps it should say,
> 	    character: Stray byte   (4194196, #o17777624, #x3fff94)

We could do that indeed.

> What are the situations where a user is likely to see these stray
> bytes.

There pretty much shouldn't be any in multibyte buffers.

> When visiting a binary file, of course; but in that situation,
> nobody will be surprised or disappointed.

And presumably for binary files, the buffer will be unibyte.

> (It is also not clear to me what "ASCII compatible" means in this
> context.)

It means that the lower 128 chars coincide with those of ASCII.


        Stefan