This happens when you do a set list , so you should read :h 'list' , and not ask about it here. Everything you need to know about this $ is listed in the help.
The second question (dividing line at the end of the line) answers in :h getline() . I also doubt that the file really does not have NL, so write here how you came to the conclusion: "The file does not seem to receive" \ n ".
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