A GNU Emacs feature that I'd find helpful on occasion is its ability to
turn on line wrapping for very long lines...
I'm running into this issue again right now, looking at some log files
of a system I'm building.
This is not FILLING but WRAPPING; a long line is displayed with little
flags on the right side, and characters that don't fit on the screen are
displayed on the next line below. This can go on for as many (screen)
lines are necessary to hold the (file) line. The file line is still
just one physical line, though.