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Default ordering of multiple non-spacing marks
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Precomposed/decomposed diacritic character representation
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Hangul jamo vs. johab and jamo representation alternatives
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CJK compatibility ideographs
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Other backwards compatibility duplicated characters
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Separately coded Indic length/AI/AU marks
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Glyphs for vertical variants
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Croatian digraphs, other ligatures (Latin, Arabic,...)
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Various variant punctuation (apostrophes, middle dots, spaces,...)
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Half-width/full-width characters (Latin, Katakana and Hangul)
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Vertical variants (U+FE30...)
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Presence or absence of joiner/non-joiner
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Superscript/subscript variants (numbers and IPA)
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Small form variants (U+FE50...)
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Upper case/lower case
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Similar letters from different scripts (varying degrees) (e.g. "A" in Latin,
Greek, and Cyrillic)
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Letterlike symbols, Roman numerals (varying degrees)
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Enclosed alphanumerics, katakana, hangul,...
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Squared katakana (units,...), squared Latin abbreviations,...
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CJK ideograph variants (varying degrees, in particular general simplifications,
backwards-compatibility non-unifications, JIS 78/83 problems)
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Ignorable whitespace, hyphens,... (sorting)
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Ignorable accents,... (sorting)
