libdwarf reads and/or writes DWARF debugging information in Elf object files. dwarfdump uses libdwarf to read object files and print the DWARF content in a readable fashion. libdwarf implements the DWARF2 (and later) standard by providing function interfaces that abstract away many DWARF implementation details (the writer code only emits DWARF2 so far). The source also includes implementations of a few tree search (tsearch) algorithms (balanced, red-black, and binary).
Termdebug is a set of utilities for recording and replaying the input and output of terminal programs. Its main goal is to aid in developing and debugging terminal programs. Other programs such as termrec/termplay, nethack-recorder/player, and script/scriptreplay only record the output. However, when debugging an interactive terminal program, the input is often as important as the output.
pymiproxy is a small, lightweight, man-in-the-middle embeddable proxy capable of performing HTTP and HTTPS (or SSL) inspection. The proxy provides a built-in certificate authority that is capable of generating certificates for SSL-based destinations. Pymiproxy is also extensible, and provides two methods for extending the proxy: method overloading and a pluggable interface. It is ideal for situations where you're in dire need of a proxy to tamper with out- and/or in-bound HTTP data.
PHP Error aims to make understanding initial error reporting as fast as possible. When an error strikes, you get a full syntax-highlighted stack trace, with code snippets from the relevant files and improved error messages, displayed with CSS3. It works for AJAX requests, too, with no JS changes or plugins required.