Browser extension creators selling users' browsing history [German source]

https://www.ndr.de/nachrichten/netzwelt/Nackt-im-Netz-Millionen-Nutzer-ausgespaeht,nacktimnetz100.html

A German TV team acted as a big data company, tried to buy user data from browser extension creators and got access to billions of records. Facebook and other personalized URLs make it easy to find out who the records belong to. The one extension that's specifically named is WOT (Web of Trust).