Comparison is performed line by line, "Enter" should act as a separator, spaces are considered line continuation.
"Combine Lists" - Merges two lists into one, one repeating line remains in the resulting list, unique values are preserved. The second field contains repeated lines.
"Remove duplicates" - Deletes all duplicate lines of the list, leaving only unique ones. The second field contains deleted lines.
"Remove unique" - Leaves one of the duplicate values, unique values are removed. The second field contains the unique lines that have been removed.