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Swarm allows all string-typed header fields to have multiple lines as well as encoded words. Swarm stores the header value as-is with the object metadata. It decode the value when Swarm needs to use that value (such as for metadata indexing). Swarm decodes header fields into Unicode and then operates on the decoded values. The original encoded persistent headers remain safely stored with the object and are returned when the object is retrieved.
See See Encoding Non-ASCII Characters in Metadata for Swarm's handling of metadata.
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