TaggedSeq

Tags in sets

Conway introduced optional 258 tags in certain items that are considered sets semantically but encoded as arrays in CBOR.

Semantics: Tag 258 can be applied to a CBOR array data item to indicate that it is a set. Sets should be handled similarly to CBOR maps: a set that has duplicate items may be well-formed, but it is not valid. Like CBOR map keys, data items in a set do not need to be of the same type.

https://github.com/input-output-hk/cbor-sets-spec/blob/master/CBOR_SETS.md