diff where lines are mostly the same but out of order?

sort can be used to get the files into the same order so diff can compare them and identify the differences. If you have process substitution, you can use that and avoid creating new sorted files.

diff <(sort file1) <(sort file2)

I made a script for this which keeps the line sequence intact. Here's an annotated version of the important lines:

# Strip all context lines
diff_lines="$(grep '^[><+-] ' | sed 's/^+/>/;s/^-/</')" || exit 0

# For each line, count the number of lines with the same content in the
# "left" and "right" diffs. If the numbers are not the same, then the line
# was either not moved or it's not obvious where it was moved, so the line
# is printed.
while IFS= read -r line
do
    contents="${line:2}"
    count_removes="$(grep -cFxe "< $contents" <<< "$diff_lines" || true)"
    count_adds="$(grep -cFxe "> $contents" <<< "$diff_lines" || true)"
    if [[ "$count_removes" -eq "$count_adds" ]]
    then
        # Line has been moved; skip it.
        continue
    fi
    
    echo "$line"
done <<< "$diff_lines"

if [ "${line+defined}" = defined ]
then
    printf "$line"
fi