Jeffrey Walton [off-list ref] writes:

I needed to install Git on Ubuntu 8. Git seems to work Ok for most
task, but this is unusual:

    $ git diff
    WARNING: terminal is not fully functional
    -  (press RETURN)

Here's the terminal:

    $ echo $TERM
    xterm-256color

A short answer.  You are using "less" as the pager, but it is not
working with your terminal.  Likely reason is perhaps you are
missing terminfo/termcap database entry for that terminal.

I have working xterm-256color, so

	$ TERM=xterm-256color less README.md

works as expected, but using a (bogus) terminal that no system would
have ever heard of, e.g.

	$ TERM=no-such-terminal-exists less README.md

results in exactly the symptom you are observing.

Something to try quickly would be:

$ export TERM=vt100; less README.md

As the termcap/terminfo entry for vt100 is usually more widely
available, this may unblock you.

It seems like loss of colors on an old platform is not that important.
However, the message being printed creates an actionable item that
needs attention. I think no message would be a better option.

You would want to redirect it to folks who work on "less" ;-)