tty-format.el adds FileFormats for ANSI SGR escape sequences and backspace overstriking. Get it from

ANSI is converted to TextProperties using AnsiColor. AnsiColor can already make such conversions, but as EmacsOverlays. Text properties make it possible to copy the faces into another formatted document like EnrichedMode.

Both ANSI and backspacing are tty oriented, and you’d like to think by now in their death throws, but are still sometimes found in text files. The aim of tty-format.el is just to make such files viewable.