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As of v1.1.0, there are two types of sequenced segments: additive and single use. Additive sequenced segments are denoted with [ and ], and are inserted starting with their designated sequence and remain in place for future identifier attempts. Single use sequenced segments are indicated with an additional = inserted after the open bracket. So, for example, the segment [1:.(M:1)] will be inserted into the second and each subsequently generated identifier candidate, while the segment [=1:.(M:1)] will only be inserted into the second generated candidate (and no subsequent candidates).
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