The documentation is incorrect. We should keep the current behavior of ignoring the BOM and otherwise continuing as normal. The situation is annoying from many angles, but the presence of a BOM changing the behavior of a file that may otherwise be entirely plain ol' ASCII is going to lead to real pain when debugging. I wouldn't want an invisible sequence to start turning on utf8.pm's behavior normally, and even less so as a backward incompatible change. UTF-8 BOMs are best ignored. (Also, best never written out, but that's another matter.) --- via perlbug: queue: perl5 status: new https://rt.perl.org/Ticket/Display.html?id=121292