Feedback on the proposal to change U+FFFD generation when decoding ill-formed UTF-8

[Doug Ewell via Unicode]

L2/17-168 says:

"For UTF-8, recommend evaluating maximal subsequences based on the
original structural definition of UTF-8, without ever restricting trail
bytes to less than 80..BF. For example: <C0 AF> is a single maximal
subsequence because C0 was originally a lead byte for two-byte
sequences."

When was it ever true that C0 was a valid lead byte? And what does that
have to do with (not) restricting trail bytes?
 
--
Doug Ewell | Thornton, CO, US | ewellic.org