Please get "0" to work in classifications.
Current behavior: 0 is ignored in any classification column
Exprected behavior: 0 is treated as any other character while importing
I second that one.
A few month ago I did some tests. A blank is also not allowed as first character. I'd recommend to allow classification of i.e. " hello", too.
Other restrictions (probably ok to let them "forbidden"):
";" is not allowed at all. Neither is "crlf" (don't ask). And of course "#".
I just came across this idea that dates from 7 years ago ... and nothing has changed!