How to read the result
Lines that exist only in the new text are marked as added, lines that exist only in the original are marked as removed, and everything else is unchanged. When a line was edited, you'll see the old version removed and the new version added right next to each other.
Ignoring changes that don't matter
Turn on “Ignore spacing” when text was re-indented or re-wrapped, and “Ignore capitals” when only the letter case changed. That leaves just the edits you actually care about.