ENet for C# wraps the C-language ENet networking library. For games and other realtime applications, if you use TCP, old data can hold up newer data, even if it is no longer relevant (old positions, etc.). Your players will perceive any lost packet as a "lag burst". ENet supports multiple in-order streams of data, and allows you to decide on reliability on a per-packet basis. The library is useful for both client-server and peer-to-peer architectures.
mdp stands for "Mot de Passe", which means "password" in French. It wraps GnuPG for encryption and deals with all the small details of generating, managing, and fetching your passwords. It is similar to many other programs, but differentiates itself with simplicity (not button-driven simplicity, but with a Unix less-is-more style). For example, beyond the use of GnuPG for encryption, it lets you use your own editor to manage your passwords, categorize them, and delete them. In order to avoid passwords lingering on your screen, the results from the queries are displayed through a custom pager which is cleared after a customizable timeout (defaulting to ten seconds).
xmlsd is a library that wraps expat in order to simplify XML use in C programs as well as adding rigid rules to an XML structure. The idea is to have XML structures that can be passed over the network with implicit parameter verification. This in turn enables back and forth chattering between applications.
Lhasa is a Free Software replacement for the Unix LHA tool, for decompressing .lzh (LHA/LHarc) and .lzs (LArc) archives. The backend for the tool is a library, so it can be reused for other purposes. Lhasa aims to be compatible with as many types of lzh/lzs archives as possible. It also aims to generate the same output as the (non-free) Unix LHA tool, so it will act as a drop-in free replacement.