bug#1726: 23.0.60; end-of-sentence and non-breaking space

[Richard M Stallman]

    > When I type C-x = at a non-breaking space, it tells me that it
    > has code 160, hex a0.  But when I execute (insert "\xa0"),
    > it inserts something that displays as `\240' and for which C-x =
    > displays this:

    >    Char:   (4194208, #o17777640, #x3fffa0, raw-byte) point=198 of 211
    >    (93%) column=5
    >
    > Is that a bug?  It seems quite confusing to me.

    ISTR that there was an extended discussion about classifying
    non-breaking spaces on this list a while back.  But I can't find it now.
    Does anyone remember the details?

I am not sure we are talking about the same question.
The issue I am raising is not one of classifying it,
it is that these two different character codes get used
and I don't see an explanation of what's going on.