About [[MediaWiki:Apihelp-wikigrokresponse-param-subject id/en]]

OPEN This issue is open, waiting for action by MaxSem

Should not WikiData be a variable $wikidata like elsewhere?

It should be a parameter, configurable with the name of any Wikibase instance. Or it should say "Wikibase instance".

But is wikigrok thought to work with anything other than Wikidata? Probably better file this as bug to make it project-agnostic.