What is the Unicode U+001A Character? Aka 0x1A

Question

The U+001A character appears frequently in error messages relating to character encoding. What is the U+001A character?

Answer 1

As far as I can tell U+001A is a legacy character in Unicode. Its only reason for existence is that it was already defined in ASCII as the substitute character ("... used in the place of a character that is recognized to be invalid or in error or that cannot be represented on a given device."). It was also sometimes used to end a character stream (which is probably a common source of problems)

In Unicode that function is taken over by the U+FFFD REPLACEMENT CHARACTER.