Yep, it totally is the responsibility of the tool that created the file: but that tool was a Chrome plugin I don't have any control over. Since then, I've found another plugin that does generate the cookie dump with this required line, so I'd be fine removing this hack.

This line's non-existence was such a silly reason for cookielib to throw out an otherwise perfectly good cookie file, I was annoyed enough to code around it. And since I was already forced to write a named file, it was not a big reach to simply guarantee this line existed in the file.