Hm, I think some minimal explanation of what Wikidata is would still be nice, though. It could be something like this:
, which can contain data relevant to the topic.
, where data relevant to the topic can be collected.
Given that this message is likely for many people the first time they get in contact with Wikidata it would be good to have it be friendly in addition to reciting correct facts. We might even have a "Read more" link in it to allow the recipient of the message to inform themselves better about Wikidata in case they are curious.