C-x & (was: Introducing thread-safe Tramp)

[Drew Adams]

> > As Richard suggested, don't call it anything. At least do not call it any of
> > those things (it's not a command or a prefix key (sequence)).
> 
> It's definitely a command and it is used before another, so "prefix
> command" sounds about right.

`C-x &' is definitely _not_ a command.

If you want to call the command it's bound to (by default) a "prefix command", 
that's a different story. But a key sequence is not a command. It might be 
bound to a command, but it's not a command.

And if a user replaces that key binding by a different one then the command 
continues to have the same behavior ("prefix command" behavior, if you like), 
but the key sequence no longer has that behavior.