I don't think there are "multiple lines", just that you can have quite large HTTP headers and this one happens to contain a comma followed by a space, which the

I don't think there are "multiple lines", just that you can have quite large HTTP headers and this one happens to contain a comma followed by a space, which the text view is using to word-wrap. See e.g. https://web.archive.org/web/20180605011201/https://www.list-unsubscribe.com/technical/ https://web.archive.org/web/20180605011201/https://www.list-... for a better example.