The message wikibase-monolingualtext has some HTML and ($1). It is optional and not translated to any languages. It can probably be completely removed. For languages that need different parentheses characters, there is the core MediaWiki message parentheses, and the HTML can be just constructed in the code in run time.
(The message is actually in WikibaseLib, but I couldn't find a project tag for that, so tagging as WikibaseRepository.)