On gnu.org site there is GNU Head that can be display on terminal it have XTerm compatible (Normal documented ANSI Codes) but it also contain TTY version (it work on Cygwin, didn't test in XTerm or real terminal).
It contain text like:
]Pf767676 and then normal
[1;37m which is documented for instance on wikipedia. What is
]Pf767676 and where it's documented?