Using the Encoding Declaration

This rule is here because it allows the use of tricks such as those described in the appendix on Autodetection of Character Encodings. We recognize that although the Web provides a method for a server to tell the client what kind of encoding is being used, sometimes it breaks down, and sometimes there's no server (like when you're reading something straight off a disk).

In these situations, everything works much better if entities give the processor some help in figuring out how things are encoded.

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