Support for "confusables"?

[WardBrian]

UTS 39 specifies a list of "confusables" as well as "intentional confusables". These are characters like the greek and cyrillic characters which look identical but are not normalized to each other.

It would be very helpful if there was some way to identify these with each other, particularly the intentional confusables as many of them are valid XID characters.

Rather than an extra database of values here, there is also an algorithm given in section 4 ("Confusability Detection") which could be placed in the uunf package