wbsearchentities has a "props" param with only one available value: “url”. The URL is already included in search results by default, which means that this parameter does nothing.
We should either fix the parameter, or remove it. Either is would be a breaking change, since existing clients might rely on the API returning the URL by default now, and removing the parameter is of course also a breaking change.
Example:
https://www.wikidata.org/w/api.php?action=wbsearchentities&format=json&search=potato&language=en
https://www.wikidata.org/w/api.php?action=wbsearchentities&format=json&search=potato&language=en&props=url