Typographer's mark for a footnote reference is my guess.
Since this was a governmental correspondence, this might be a kind of censure mark???
You'll see that it appears where some punctuation is probably indicated. Say a double-dash (--) or quotation marks (").
When the website's html fonts don't read double-dashes or prefers one quotation mark over another (i.e., " vs the curlicue upside down commas), it will replace these with an error code -- like "—".