Sdb.txt
sdb.txt is a file found in the scripts directory.
SDB most probably stands for String DataBase.
It's a text file containing strings in sequential order. The index number for each string entry is therefor the line number starting from 0.
It is not possible to insert or delete strings without having to modify each string reference inside the script files. Adding or replacing string is possible by the simple means of a text editor like Windows Notepad.
Two sort of strings exist, a quoted string and a non-quoted string. Quoted strings normally begin and end with a " character. Please note this character can be replaced with random characters because the fact that a string is quoted or non-quoted is solely determined by the script files and not by the string database!