This ACTS as a "signature" or "byte-order mark (BOM)" to identify the encoding and byte-order used in a file.

这作为一个“特征符”或“字节顺序标记(byte - order mark, BOM)”来识别文件中使用的编码和字节顺序。

youdao

If the BLOB XML stream contains a byte-order mark (BOM), it is used to determine the assumed code page of the data inside the BLOB.

如果BLOB xml流包含一个byte - order mark (BOM)，那么可以用它来确定BLOB中的数据所设的代码页。

youdao

The Unicode Byte-Order Mark (BOM) in UTF-8 encoded files is known to cause problems for some text editors and older browsers. You may want to consider avoiding its use until it is better supported.

意思是说使用utf-8的格式编码会在一些编辑器和老的浏览器上产生问题，最好是考虑避免这些问题，除非它们得到更好的支持。

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