What is a BOM?
For UTF-16 and UTF-32 the byte ordering has to be known (in fact we should refer to UTF-16LE, UTF-16BE, UTF-32LE, UTF-32BE to take into account the endianness of the encoding). In order to avoid incorrect interpretation of these encodings a Byte Order Mark (BOM) may be put at the beginning of documents: it consists in a sequence of bytes that identifies both the encoding (UTF-16 or UTF-32) and the byte ordering used (Little Endian or Big Endian).
Although UTF-8 does not require any byte ordering information, a dedicated BOM can be used with this encoding: its primary purpose is to differentiate UTF-8 from other byte-oriented encodings. If not interpreted this marker takes the form of the 3-characters sequence "" (in ISO-8859-1 or CP1252): a document starting with this sequence must be read with an UTF-8 enabled software.
© 2001-2019 Fair Isaac Corporation. All rights reserved. This documentation is the property of Fair Isaac Corporation (“FICO”). Receipt or possession of this documentation does not convey rights to disclose, reproduce, make derivative works, use, or allow others to use it except solely for internal evaluation purposes to determine whether to purchase a license to the software described in this documentation, or as otherwise set forth in a written software license agreement between you and FICO (or a FICO affiliate). Use of this documentation and the software described in it must conform strictly to the foregoing permitted uses, and no other use is permitted.