This is a XChat/HexChat plugin. Seen database made with sqlite3 and python basic use: /seen <nick>
http://www.w3schools.com/sql/sql_wildcards.asp
% = A substitute for zero or more characters. [Supported]
_ = A substitute for a single character. [Supported]
[] = Sets and ranges of characters to match.
[!] or [^] = Matches only a character NOT specified within the brackets