Comment by necovek

That says roughly the following when applied to UTF-8:

"The base ASCII characters and control characters in UTF-8 are the same single byte codepoint as ISO-8859-1 while all other characters are represented by multiple bytes where each byte is not one of the invariant ASCII characters. Therefore, legacy applications could simply ignore codepoints that are not recognized."

(I know nothing of EBCDIC, but this seems to mirror UTF-8 design)