> No mention whatsoever of the $TERM environment variable. sigh

I have mixed feelings about this... Sometimes I feel young and reckless and want to just output whatever I need without checking $TERM. In practice, all modern terminal emulators are essentially xterm-256color compatible. If something breaks, the worse you get is some funny characters. Is that such a big deal? Much better than propagate the silly termcap/terminfo complexity.

By the way, xterm supports sixels since forever.