[Karl Eichwalder]

> On my US keyboard both keys showing "accents" are not symmetrical:
> `...'.

Neither on mine, actually.  So, the keycaps are not showing ASCII.  Anyway,
I would not take the keyboard, your or mine, as a reference.

> Using ISO-8859-1 these are the symmetrical accents: `...´ (where ´
> is 8bit).  Using a recent xterm with recents fonts this is visible.

I do not remember the text of ISO 8859-1, nor if it addresses that problem.
I'm using ETL fonts, which do something sensible.  I'm including a picture
of a small part of this message composition buffer...