WBL is a really simple tool that can be used in a .qmail file for managing a white/black list of email addresses. It serves as a pre-filter to allow known-good friends and associates bypass the usual gauntlet of filters. Note that WBL is not intended to be a spam filter, it is simply an easy-to-use whitelist/blacklist management tool that serves to keep email that you really want to see out of your normal filters.
whatsnewfm is a filter for the daily freshmeat newsletter. It shows only news items that you haven't seen before (so you don't have to read about every update of applications that you aren't interested in). You can also set up a list of "interesting" applications where you want to be informed of every update.
xlHtml converts an Excel spreadsheet file (.xls) into highly-optimized HTML. It includes scripts to allow it to be used as a Netscape or mutt plugin and as a xls handler for Apache. The program currently supports string, blank, boolean, error, integer, floating point, hyperlinks, and formula cells. It can also output in XML, tab delimited, or comma separated values (CSV).
xml2sql-v is based on expat and is a quick and dirty solution to transform the content of any well-formed XML file into SQL INSERT statements such that you can postprocess the content of the XML data with SQL. The XML file is neither tested for correctness nor is it checked to contain anything reasonable. The insert statements will have the UTF-8 characterset but there are 3 more utilities (entityfix, latin1-utf8, and utf8-latin1), to fix broken HTML entities within the XML files, convert "forgotten" Latin1-Characters into proper XML entities, and convert the output back to Latin1 for easy insertion into the database.
xtee (cross-tee/expanded tee) is a program for building complex pipelines. It resembles the tee command, except that instead of copying stdin to stdout, it copies an input file to stdout and stdin to an output file. You can use xtee for building things like a bidirectional HTTP filter (using netcat and sed).
ytnef_cg_filter.pl provides a content filter program for the Stalker CommuniGate Pro email server that performs extraction of TNEF (winmail.dat) attachments by utilizing ytnef. It also has the ability to scan attachments with Clam Antivirus, as well as block them based on regular expressions. Its goal is to ease interoperability between mixed Windows and Linux workgroup environments.