No, that is not a bug and there was never such a thing as "manually" adding a trailing newline. All tools add newlines automatically where they should be. Unix

No, that is not a bug and there was never such a thing as "manually" adding a trailing newline. All tools add newlines automatically where they should be. Unix has ALWAYS defined a line of text as being terminated by a newline. The last line in the file is not an exception.