While I was parsing the Snort regex set I found a very odd character class syntax, like [\x80-t] or [\x01-t\x0B\x0C\x0E-t\x80-t], and I can't figure out (really no clue) what -t means. I don't even know if it's standard PCRE or a sort of Snort extension.
Here are some regular expression that contains these character classes:
/\x3d\x00\x12\x00..........(.[\x80-t]|...[\x80-t])/smiR
/^To\x3A[^\r\n]+[\x01-t\x0B\x0C\x0E-t\x80-t]/smi
PS: please note that \x80-t is not even a valid range in the standard way because character t is \x74.