= Compatibility equivalence
<Compatibility equivalence> relates <Unicode> sequences whose compatibility decompositions agree, including distinctions that may matter in some contexts. It includes canonical matches but can additionally identify characters differing in formatting or conventional presentation. <Unicode normalization> forms NFKD and NFKC use these broader decompositions.<Unicode Normalization Forms by the Unicode Consortium>[§1.1, Compatibility Equivalence; §1.2, compatibility normalization forms]{ref}
For example, the circled digit `U+2460` and ordinary digit `U+0031` both normalize to `1` under NFKC. NFC retains their distinction. A circled list marker and an ordinary numeral can therefore become indistinguishable under compatibility normalization, even when an application wanted to preserve the original notation. The choice is a representation policy, not a test of visual similarity: applying compatibility normalization requires deciding which distinctions the task may safely discard.
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