It doesn't mean anything, just when your message is too long it's put onto a second line, and anything on the second line is brown, not sure why this is, but it means nothing.
In older versions all of the names appeared in black without angled brackets. Your own messages appeared in brown instead.
Changes were implemented on top of the existing system. You see the first bracket in brown because somebody forgot to add an extra colour code for it, and the text on the new line doesn't keep the colour codes from the first line.