GNU Teseq is a tool for translating files that contain control characters and terminal control sequences, into human-understandable text. It is intended to aid in debugging problems in terminal emulators, software that makes use of special terminal features, and interactions between the two. Teseq is primarily targeted at individuals who possess a basic understanding of terminal control sequences, especially CSI sequences; however, by default Teseq will try to identify and describe the sequences that it encounters, and the behavior they might produce in a terminal. Teseq describes control functions as they are interpreted by VT100-compatible terminals, and/or terminals compliant with the ECMA-48 / ISO/IEC 6429 standard. Teseq does _not_ support describing control functions according to terminal-specific definitions in a database such as termcap or terminfo, though future versions may include limited support for that (*note Future Enhancements::). Therefore, the descriptions Teseq uses for control functions may not necessarily match their actual interpretation by whatever terminal device the characters were actually intended for.