The German commissioner for data protection might be interested:
https://www.bfdi.bund.de/DE/Service/Kontakt/kontakt_node.htm...
In case you'd rather not do it through official channels (or in addition, just to keep them on their toes), may I suggest:
I can imagine such an entity, at least in Germany: the Schufa, a credit rating service. It's impossible to open bank accounts, get credit or phone/internet contracts without all this going into their DB.
Better hope they secure their systems. Credit rating companies are, from their model of business, rotten to the core - and pose an extremely high risk these days where everything is computerized.
Having come up working on classified systems, it pains me greatly to see such lax security.
Instead of risking their data in the motherlode of hacks occurring against Github they setup on-premise Github/Gitlab/Bitbucket/etc. then let the servers go unpatched, stay several versions behind, don't bother setting up authentication roles properly and give people more access than intended.
There are plenty of places doing on-premise right, but I definitely trust Github over the average undermaintained on-premise installation.
I guess the other side of that argument means that mentioning who sells it shouldn't be a problem either.
But you need a consent to collect that data in the first place.
I'm simply waiting for the day when there will be a hack like this on the European continent, it's scary what sits in lightly protected databases, especially if you consider the probable sources of data like this and that - at least in Europe - it would be illegal to create such a DB without the consent of those whose information is stored in them.
We've lost control is the perfect way to describe things.