The Encodings section is optional, and follows the collation sequence. It is not useful for single-byte character sets.
The Encodings section lists which characters are lead-bytes, for multibyte character sets, and what are valid follow-bytes.
For example, the Shift-JIS Encodings section is as follows:
Encodings: [\x00-\x80,\xa0-\xdf,\xf0-\xff] [\x81-\x9f,\xe0-\xef][\x40-\x7e,\x80-\xfc]
The first line following the section title lists valid single-byte characters. The square brackets enclose a comma-separated list of ranges. Each range is listed as a hyphen-separated pair of values. In the Shift-JIS collation, values \x00 to \x80 are valid single-byte characters, but \x81 is not a valid single-byte character.
The second line following the section title lists valid multibyte characters. Any combination of one byte from the second line followed by one byte from the first is a valid character. Therefore \x81\x40 is a valid double-byte character, but \x81 \x00 is not.
