From Monarchists.Wiki

This is a hyphen (-). It has the same function as the code - or the symbol -. It comes in handy when an editor wishes to make explicit that he or she really does intend a hyphen, to discourage other editors from changing it to an ndash or other punctuation, or when using an explicit hyphen may cause technical issues, such as with the -{ wiki syntax for language converter. By allowing {{hyphen}} to be coded instead of -, it avoids objections to HTML escaping. (There does not seem to be a symbolic escape e.g. ‐.)